cascades2 design review experimenters data

8/2/2019 Cascades2 Design review Experimenters Data

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CASCADES2

reflight of

the Changing Aurora: in Situ and Camera Analyseof Dynamic Electron precipitation Structures

vehicle 40.023

Experimenter Package

Design Review

8 March 2008

Dartmouth College

Cornell University

University of New Hampshire

University of Alaska, Fairbanks

Alfven Laboratory, KTH

University of California, Berkeley

SRI

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Table of Contents

1.0 Experiment overview2.0 Instrumentation and subsystem array3.0 Experiment responsibilities and heritage

4.0 Testing required5.0 Mechanical systems6.0 Power7.0 TM and interface connections8.0 Times and altitudes of experiment events9.0 Squib circuits and deployments

10.0 Monitors11.0 Aspect sensors12.0 Radar13.0 Trajectory data14.0 Outgassing, magnetic cleanliness, RFI15.0 Vehicle performance16.0 Range support17.0 Launch conditions18.0 Comprehensive success criteria19.0 Minimum success criteria20.0 Open questions and concerns21.0 List of contacts

A.0 Cornell Instrumentation Appendix

B.0 Imager Instrumentation AppendixC.0 SMILE Magnetometer AppendixD.0 Dartmouth Instrumentation Appendix

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1.0 Experiment Overview

Science: The purpose of the Cascades2 sounding rocket mission is the investigation of motionsand structure of electron precipitation in pre-midnight poleward edge discrete aurora. Ourprincipal scientific objective is the investigation of spatial and temporal structures within

electron precipitation and low-frequency electric field activity in the topside ionosphere.Cascades will address the following questions:

Does dynamic aurora move with respect to the background ionosphere? How much?Does it matter?

What is the spatial (as opposed to temporal) variation of auroral parameters like Band E? What does this mean for theories of energy transfer?

Alfven waves carry disturbances and changes down to and through the auroral zone,giving us structured and dancing aurora. They are pretty: do they matter? Are thesestructures significant for magnetosphere/ionosphere coupling? Do direct observationsof these motions validate theories and models?

Payload: The experiment consists of a main payload and four subpayloads: two identicalwire-boom electric field subpayloads (E-field subpayloads) with GPS position and timing,and two free-flying particle detector subpayloads (particle-free-flyers, or PFFs) with GPSposition and timing. The payloads 100 km magnetic footpoint will be tracked in real timeby a dedicated narrow-field auroral camera from Kaktovik or Toolik Lake, and these imagestogether with those from all-sky cameras and from an onboard, downward-looking camerawill provide the auroral context for the in situ plasma measurements. We are planning alaunch from the Poker Flat Research range in winter 2009.

Technology: Our primary technology development objectives are the development of smallautonomous payloads (i.e., particle free flyers, a.k.a., PFFs), GPS packaging and integrationwith instrumentation, and ties to small low-resource sensorcraft development such as cubesatmissions.

Science Team: There are many investigators from many different institutions who willcontribute to the Cascades2 mission. Kristina A. Lynch is the principal investigator and isresponsible for the overall mission. A complete list of investigators, engineers, and studentscan be found in section 20 of this document and their contributions to the mission are listedbelow. Dartmouth College, with the support of the co-I institutions and WFF/NSROC, willbe responsible for the overall system design, particle detectors and the PFF subpayloads.The University of New Hampshire will be responsible for the onboard camera to image the

visible aurora, and the thermal electron detectors. Cornell University will be responsible forproviding the electric field and plasma wave subpayloads. Cornell is also responsible for the5 GPS systems. KTH will provide the new SMILE magnetometer for which we are providinga test flight; they will also field a ground camera during the launch campaign. SRI providesPFISR support, and our theory collaborators at UCB, Cornell and KTH will work with theinstrumentation science team in mission planning and data analysis.

Heritage: This is a reflight of 40.017. Our design plan, after a 4-year period, is to maintainthe identical design to the extent reasonable and possible. We plan to make changes that

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will make things easier, using lessons learned last time. With the exception of the PFFsubpayloads and their deployment system, all other instrumentation and subsystems havedesign and flight heritage (in addition to Cascades1), as noted throughout the text. Inparticular we build heavily on the highly successful Sierra payload; the E-Field subpayloadswere designed for Sierra and were flown again on Sersio and ROPA. The Cornell electric

field package is a mature design, after Sierra, Sersio, and ROPA; the Sersio version wasidentical to those proposed here, with an ERPA, and with snapshot HF capability. Thedeflectable aperture electron detector was designed for the Enstrophy mission; the deflectableaperture is a simple modification of an instrument with extensive UNH sounding rocket flightheritage. Similar aperture deflection designs have been used by other experimenters onFreja and on FAST. The main payload particle detector deployers, hinged booms, have beenflown on a number of missions. The PFF deployment system was developed and tested forCascades1. The onboard imager is comprised of mostly commercial parts with flight heritage;the first version was flown on Sersio and iterated designs have been used on ROPA. For theground observations, the UAF/GI investigators have many years of experience making opticalauroral observations and have participated in many rocket programs.

In contrast to our basic instrument suite with extensive heritage, we are also taking theopportunity this time to provide a test flight for the KTH SMILE magnetometer instrument,a new small science magnetometer with potential use for future low-resource small sciencepayloads.

2.0 Instrumentation and Subsystem Array

The five Cascades payloads are intended to form an array such that the two Cornell sub-payloads separate along the magnetic field direction, and that the two particle free-flyers(PFFs) form an L-shape with the main payload in the perp-B plane. An inertial ACS sys-tem is required so that the array can be configured with respect to the apogee magnetic fieldline. Figure 1 illustrates the concept.

2.1 Main-Payload Instrumentation and Subsystems

2 Heeps (Hemispherical Energetic Particle Spectrometer) particle detectors mountedin forward deck structure on short hinged booms (see Figures in Appx D.):

HEEPS-e- (HE): electrons, 10 eV to several keV swept electron energy detector,32 one msec energy steps per sweep, 32 sweeps/sec (sweep synchronized to GPS).Imaging over 360 degrees in 30 bins. G 1.2e-4/cm2/sr/eV/eV. This detector isa copy of the deflectable HE on the PFFs, but the deflection system will not beactivated on the (ACS-controlled) main payload.

HEEPS-ion (HI): ions, 6eV to few 100eV, 16 sweeps per 1.024 sec, 32 2 msecsteps. Imaging over 360 degrees in 64 bins.

BAGEL (Bg): high-speed field-aligned electron detector mounted fixed in center offorward deck structure (no deployment). 20 eV to 2 keV in 32 1/4 msec steps, 125sweeps/sec. (See Figure in Appx D.)

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Bo

PFRRAMISR Kaktovic

E and B along Bo

e- across Bo

Fast e- down Bo

Image down Bo

Ground cameras

Radar

Figure 1: Cascades payload array.

Auroral imaging camera: with motorized despun camera. Looks down the field linefrom the aft end of the main payload. (See Figures in Appx B.)

Science magnetometer: deck-mounted below Bagel instrument. (See Figures in AppxD.)

COUGAR GPS receiver: for 5 meter positioning and microsecond timing; GPS 1 PPSclock embedded in TM stream.

SMILE magnetometer: small test-flight magnetic field sensor. See KTH appendix (C)for details.

2.2 Cornell Subpayload Instrumentation and Subsystems

This subpayload is described in detail in Appendix A. It contains:

Science magnetometer on rigid mount (no deployment).

COWBOY (Cornell Wire Boom Yo-Yo) E-field booms with damper system; wire boomsare 12 meters tip-to-tip.

DC/VLF/HF E-field plasma wave instrument (DC to 2.4 MHz).

COUGAR GPS receiver for 5 meter positioning and 150 nanosecond timing. GPS-based telemetry synchronizer.

ERPA thermal electron plasma sensor.

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2.3 PFF Instrumentation and Subsystems

This freeflyer is described in the mechanical section below and in the NSROC material. Itcontains:

HEEPS-e-deflectable: Deflectable-aperture energetic electrons. 10 eV to several keV

swept electron energy detector, 32 one msec energy steps per sweep, 32 sweeps/sec(sweep synchronized to GPS). Imaging over 360 degrees in 30 bins. G 1.2e-4/cm2/sr/eV/eV.Deflectable aperture points 6-deg-field-of-view along local -B within 20 degrees of PFFspin axis. (See Figure in Appx D.)

Science magnetometer on rigid mount (no deployment).

COUGAR GPS receiver for 5 meter positioning and microsecond timing; GPS 1 PPSclock embedded in TM stream.

Sun sensors

2.4 Ground based sensors

Kaktovik or Toolik Lake narrowfield and all-sky cameras: Narrowfield camera real-timetracked to payload footpoint

Poker narrowfield and all-sky cameras

PFISR incoherent scatter radar based at Poker.

3.0 Experiment Responsibilities and Heritage

Responsibilities:

- Main Payload NASA/NSROC Dartmouth Cornell UNH KTH- Structure, deck, skins X- Nosecone eject systems (LEO/FEOS) X- Power/ timer/pyro-firing systems X- Science magnetometer X- At tit ud e Con tr ol Sy ste m (gy ro -ba se d A CS ) X- Release Mechanism (pin puller) for Detector Booms X- Subpayload Ejection:E-field subpayload Deployer X- Subpayload Ejection: PFF Deployer X- 10 Mb/s PCM encoder X- Particle Instruments X- Particle detector booms X- Imager X- Sun sensor electronics X- GPS Wrap-Around Antenna X- GPS Receiver #1 X- GP S R ec ei ver # 2 ( re qui re d b y NAS A/ NSR OC ) X- GPS Internal Re-radiator to subpayload GPS (splitter) X- GPS Internal Re-radiator to subpayload GPS (antenna)- TM Transmitter & Antenna X- Image compression for UNH Imager X- SMILE magnetometer X

-E-field Subpayloads (2 Identically Configured)- Structure, deck, skins X- Subpayload Ejection Systems (Springs) X- Power / Timer / Pyro-firing systems X- Science/Aspect Magnetometer X- Solar Aspect Sensor X- COWBOY boom system with damper X- Pyro Release mechanism for COWBOY booms (cable cutter) X- Rotation angle monitor for COWBOY boom system X- 4.8 Mb/s PCM encoder X- GPS Receiver X

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- GPS Preamp X- GPS TM synchronizer X- TM Transmitter and Combination S-band/GPS Antenna X- ERPA X

- PFF Subpayloads (2 Identically Configured)- Structure X- Skins X- Science/Aspect Magnetometer X

- Particle Instruments X- Sun sensor electronics X- PCM encoder X- GPS receiver X- GPS preamp and antenna X- TM Transmitter and Antenna X

Heritage:

Previous MissionsSe rsi o Si err a C ap er Sc if er Pha ze 2 R OPA Sc if er 2

Cascades Experiment (35.035) (40.014) (40.012) (40.006) (40.010) (40.020) (40.021)- Dartmouth -- HEEPS X X X X X X X- Dartmouth -- High-speed Bagel (new)- Cornell -- HF E-field X X X- Cornell -- DC/VLF E-field X X X X X X X- Cornell -- B-field X X X X X- Cornell -- GPS TM Synchronizer X X X- Cornell -- GPS Receiver X X X X- Cornell -- Yo-Yo boom X X X- UNH -- Imager X X- KTH -- SMILE (new)

4.0 Testing Required

Besides the standard environmental testing that is done at the payload level during integra-tion at NASA WFF, the following tests are required by the experimenters in order to provethe flight readiness of several new systems on the Cascades2 payload. We anticipate thatthese tests would take place prior to the start of integration at WFF, during the final stagesof development of these systems.

PFISR interference tests

Pre-integration of the SMILE/TM interface in August

Magnetic cleanliness testing, especially of PFFs and subs

Deploy tests

Post-integration Dartmouth instrumetation vacuum tests

5.0 Mechanical SystemsThe main payload consists of a forward experimental section, a telemetry section, an attitudecontrol system (ACS) and an imager. Sub-payloads PFF 1 and PFF 2 are located betweenthe forward experimental section and the telemetry section. Sub-payload down (E-field)is located aft of the ACS and imager. Sub-payload up (E-field) is located just under thenosecone.

We request that NASA/Wallops provide the TM and skin sections for the main payload,as well as the subpayload skins, lower telemetry section, and interior decks which serve as

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the interior support for the wireboom system, as was done for Sierra. For the PFFs, NASAwill provide the skins, transmitters and antenna.

5.1 Openings, Doors, Skins, and Skirts

The entire nosecone is ejected prior to final burn. A LEOS system is used to eject thenosecone prior to Nihka ignition in order to help achieve the apogee requirements.

After subpayload up separation and subpayload down separation, the forward experi-mental sections boom systems and PFF deployers will be exposed by ejecting the springskin section.

5.2 Booms Antennas

There will be two deployable elements on the main payload consisting of a short boomsupporting the Dartmouth HEEPS-E electron detector and a short boom supporting theHEEPS-I ion detector. The booms will utilize the short flip down arms with pin-pullerrelease mechanisms used on many previous flights, retrofitted to include a potentiometerdeploy monitor as was done for Scifer2.

For the two E-Field subpayloads, a small, light weight, and dynamically stable boomsystem for the electric field measurement is used (see Appendix A). This is a design developedat Cornell University that rapidly deploys the wire booms into a stable disk-like geometry.The initial form of this design was successfully flown on Sierra and the updated design wasflown on Sersio prior to use in Cascades; as well as on ROPA.

5.3 Subpayloads - E-Field

Please refer to Appendix A for the following discussion regarding the E-field sub-payload andCOWBOY booms. The sub-payload is configured as a short cylinder with a moment of inertiatransverse to the spin axis exceeding the spin axis moment. A concentric spool is placedaround the inner payload and positioned close to the center of mass. The spool can rotateabout the symmetry axis and is attached to the sub-payload cylinder with a combinationbearing and magnetically controlled damper. Four wire booms are wound around the spooland sensing spheres are placed at the end of each wire boom. During deployment, the wirebooms unwind like a yo-yo despin mechanism, with the exception that the outer spool willrotate with respect to the sub-payload cylinder and as the spool rotates it damps energyfrom the system. After the wire booms are deployed a pyro activated brake is engaged,which locks up the spool with respect to the inner payload.

5.4 PFFs

Description: The two particle detector freeflyers PFFs (see Appx D and NSROC me-chanical systems section) are autonomous small payloads. They carry their own TM systemsand transmit directly to the ground via 9-inch wraparound antennae. They are deployedfrom the main payload after the main payload has been aligned to near the apogee magneticfield line for the electric field subpayload deployments, so that their spin axes (and detector

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aperture planes) are nominally within 6 degrees of field alignment throughout the flight.As the trajectory carries the PFFs northward, their spin axes will move first towards andthen away from field-alignment, and the electron detector aperture deflection system willmaintain the field-line-looking capability using the onboard magnetometer. This deflectionsystem will also correct for misalignments from possible PFF coning. The design is based

on a standard diameter and standard NASA TM components. It is a very compact payload,but does not require a great deal of expensive redesign or miniaturization.

Constraints: The design of the PFF is limited by the following constraints:

Stability: Deconvolution of the magnetometer data requires a simple rigid body motion,i.e., spinning and (minimal) coning about the body axis parallel to the main payloadspin axis. This requires balancing of this small payload to high accuracy, and absoluterigidity of the structure (i.e., no loose cables).

Magnetic cleanliness: The magnetometer is by definition quite close to the payload sonon-magnetic connectors, etc, must be used.

Autonomy: The PFF must work by itself with only the HVON command coming afterlaunch, triggered by deployment.

Size: The system must fit within the envelope determined by the TM antenna; thisrestricts number of battery packs, redundant systems, etc.

Spin rate: The spin rate is limited from below by the stability requirement and fromabove by the electron detector deflector system. A spin rate of a few Hz is desirable.

Ejection: The PFFs must be placed in an L-shape with the main payload, in a planeperpendicular to apogee-B, and less than 0.5 km from the main payload at apogee.

5.5 Experiment Weight & Volume Estimates

Dimensions of the main payload and PFF instruments are given in Appx D figures, togetherwith an illustration of the basic particle detector electronics box tray; dimensions for thesubpayloads in Appendix A. The following are estimates, not measurements.

Main-Payload H x W x D in. lbs.

HEDF 3.4" x 5.6" diam


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E-Field subpayloads

E & B-Field electronics 4 x 5.5 x 5.9 6

GPS Electronics 3 x 5.5 x 5.9 3

Science Magnetometer 1.5 x 1.5 x 5.9 0.5

COWBOY boom system 12 x12 x 12 6ERPA 2.7x 3.5 x 2.3 1

E-Field subpayload Experiments Total 17 lbs.

PFF subpayloads

HEDF 3.4 x 5.6 diam


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6.4 General Comments - Power Systems for Main and E-field pay-loads

Independence and grounding: For the main payload and all four subpayloads, each experi-ment should have independent control of power-on and power-off for the purposes of trouble

shooting and interference checking. The Dartmouth and UNH experiments may share asingle +28V battery pack. The +18V and -18V Cornell power should not be shared withany other user. All battery packs and telemetry systems should be referenced to ground ata single point on only one deck of the rocket chassis. We are trying to avoid noise pickupwhich may be caused by multiple chassis grounds.

18V: We require separate battery charging circuits for the +18V and -18V battery packsbecause of the substantially higher power consumption of the +18V battery compared tothe -18V battery. It is not acceptable to charge across the +/-18V battery pack this willresult in an incomplete charge of the -18V side of the battery pack. Please wire the +18Vand -18V batteries as two separate batteries (even though they may be located in the samebattery box) with completely separate charging circuits.

TEST signal: In addition to the payload power control described above, a TEST signal isrequired for the Dartmouth experiment. The TEST function requires +28V at 100mA. Thisline powers internal test oscillators for payload checks. Power to this line should come onlyfrom the umbilical so that there is no chance of the test oscillators being powered duringflight.

HVON: The Dartmouth HV ON requires +28V at less than 20mA. Altitude switch hold-off of these functions is not required. HV supplies that cannot be operated in air haveinternal altitude switches. In flight, HV should be timed to turn on (minimum altitude 160km) and remain on. For the PFFs, the HVON is triggered by the deploy.

Subs: On the E-Field sub-payloads, the 18V power to the Cornell Power Amplifier Box

needs to be supplied by a relay controlled by the electronic timer. The Power AmplifierBox takes 18V at +/-2.5A for a maximum of 10 seconds. The electronic timer will activatethe 18V to this box just prior to COWBOY wire boom system deployment. A POWERAMPLIFIER TEST function should be designed into the umbilical and test suitcase toactivate the 18V to the Power Amplifier Box, to permit testing of the wire boom systemwithout running the payload timers.

GPS: For ground testing and pre-flight use, Cornell requires a separate umbilical powersource for each of the 2 E-field Subpayload Cornell GPS receivers. The Cornell GPS receiversrequire +12V at approximately 200 mA through the umbilical. No on-board power switchingis required. This power source will be diode isolated from other power sources inside of theCornell electronics box. The other 3 GPS systems (Main, PFFs), will usa a +28ka (keepalive)

power.

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7.0 Telemetry and Interface Connections

7.1 Main Payload TM and Connector

Main payload imager TM and connector specifications are listed in Appendix B. Main pay-

load TM requirements for Dartmouth experiments are listed in Appendix D. Main payloadTM requirements for KTH (SMILE) are listed in Appendix C.

7.2 E-Field Subpayload TM and Connector(s)

Refer to Appendix A.

7.3 PFF TM and Connector

The PFFs each require a 640 kbit link, and use 10 bit words. The PFFs will be stowed insideof a main payload conductive skin section.

Time tagging of the telemetry data will be done by embedding the 1 pulse-per-second(1PPS) output from the Cornell GPS receiver into the PCM telemetry data. This will bedone by connecting the 1PPS signal to the time event module of a standard WFF93 PCMencoder. During post-flight analysis, the experimenters will decode the GPS data and notethe locations of the 1PPS in the telemetry matrix and determine the UTC time of eachtransmitted word in the telemetry for the entire flight. The 1PPS will be used in real-timeto synchronize the sweeps of the Dartmouth UNH electron detectors on the main payloadand the two PFFs. The accuracy of the sweep synchronization will be on the order of 150nS.

Experimenter requirements for PFF TM are listed in Appendix C.

8.0 Times and Altitudes of Experiment Events

A list of events from the experiment viewpoint; see Timeline for official chronology.

Main Payload Events

1. Nosecone eject prior to Nihka ignition for altitude.

2. Despin to 2Hz

3. Payload separation

4. ACS: roll control to 2 Hz

5. Aft skirt eject

6. ACS: roll control to 4 Hz 0.5 Hz for subpayload stability and remove coning; and,maneuver spin axis antiparallel to apogee B-field (spin axis points upward, away fromthe Earth; and B-field points downward, toward the Earth)

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7. Eject forward subpayload UP against apogee B-field vector @ 6-7 m/s and eject aftsubpayload DOWN along apogee B-field vector @ 6-7 m/s

8. Eject forward skirt surrounding main payload experiment

9. ACS remove cone and roll to 1.5Hz

10. Eject PFF #1 and PFF #2, perpendicular to B and to each other, 3.0 m/s; HVONat deploys

11. GPS re-rad off

12. Main booms deploy

13. Camera on; camera despin motor on

14. ACS remove cone and roll control to 1 Hz final roll rate for Imager after booms deploy

15. ACS OFF

16. Main payload HVON above 160 km, after T+200s

Subpayload(s) Events

1. Enable COWBOY damper at eject + 6 sec

2. Deploy COWBOY antenna at + 9 sec

3. Engage COWBOY brake at +61 sec

4. Disable COWBOY damper at +66 sec

9.0 Squib Circuits and Deployments

9.1 Pyrotechnics and pin pullers

On the main payload, the two fold-down booms for the electron and ion detectors will bereleased by one or more dual bridge-wire retractable actuators (pin pullers), type IMT 18CC(228-50000), to be supplied by NASA/NSROC. On each of the E-Field subpayloads, theCOWBOY wire boom systems will be released by a pyrotechnic cable cutter (Holex 2800 guil-lotine) to be supplied by NASA/NSROC. In addition, the brakes for the COWBOY booms

will be engaged by a pin puller type IMT 18CC (228-50000) supplied by NASA/NSROC.Design of the release mechanisms will be the same as flown on Sierra. Pin pullers will beneeded also for the PFF pivot releases.

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9.1 Deployments overview

The nosecone is ejected first and kicked sideways (standard NASA system) before the finalmotor burn. The E-field subpayloads each are ejected along the spin axis with a ring oftwelve springs in a circular arrangement, achieving a high separation velocity using existing

stock components while maintaining acceleration limits. After the subpayloads are separatedfrom the main, the small containment disc holding the spheres is ejected back towards themain payload (at a slow velocity), allowing the release of the wire booms. The wireboomdeployment mechanism is on an angular momentum damper assembly, allowing the release ofthe wirebooms to an orthogonal configuration. After the electric field payloads are releasedfrom the main (at 6-7 m/s separation velocity), the spring skin section surrounding themain payload particle detectors is ejected at a few m/s. The PFFs are then released (seedescription below), and finally the main payload particle booms are deployed (see descriptionbelow.) Critical examination of timer timelines and timer errors will be necessary for thismission. Note should be taken of accelerations in light of extreme subpayload separationvelocities.

9.2 Efield subpayload deployment

See Appendix A for subpayload information. Requirements for clean subpayload deploy-ments are listed in Vehicle Performance and Success Criteria sections below.

9.3 PFF deployment

The PFF payloads represent a non-negligible fraction of the total payload mass and theirdeployment will cause some despin of the main payload. Estimates show a separation velocityof about 1.4 m/s is attainable for a starting main payload spin rate of 4 Hz. This translates

to a main payloadPFF separation of just under half a kilometer at apogee. The PFFswill be deployed (simultaneously) after the electric field subpayloads, with their spin axesnominally parallel to -B at apogee. Main payload ACS roll control can be used before releaseif any adjustment is needed to achieve the desired separation velocity. It is important thatthe separation vectors between the main and each PFF be roughly perpendicular to eachother, and be in the perp-B plane.

Expectations for the PFF deploy are as follows:

A 90-deg separation array with a velocity of 32 cm/sec/Hz is attainable.

With a main payload spin of 4 Hz, a separation velocity of 1.2 m/sec gives a 360 m

separation at apogee. The PFF spin rate would be 2.8 Hz.

axisymmetry issues...

10.0 Monitors

The experimenters will use boom position monitors (potentiometers) for the main payloadHI and HE booms. The position of these two monitors will be monitored by main payload

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TM.On the PFFs, a pushbutton mechanically released at deploy will trigger HVON within

the PFFs. Breakwires on the PFF are monitored by main payload TM.On each of the electric-field subpayloads, Cornell will provide monitors for the COWBOY

boom system. An optical shaft encoder will provide angular position and angular velocity

of the rotating spool and will be encoded by the Cornell experiment.

11.0 Aspect Sensors

A 3-axis science magnetometer is required on the main payload. On the four subpayloadsthe science magnetometers will be used for aspect determination. Sun sensors will be neededfor each payload. The imager on the main payload will have its own roll rate sensor.

12.0 Radar Beacon

A radar beacon is not required by the experimenters.

13.0 Trajectory Data

Absolute trajectory knowledge is required at the 500 meter level, however, relative positioningof the five payloads is required at the 5 meter level. These requirements are satisfied by theaccuracy of the data supplied by the five Cornell GPS receivers. The relative positioningcalculations will be performed by Cornell.

14.0 Outgassing Requirements, Magnetic Material Sen-sitivity, RFI Susceptibility

Outgassing: The particle detector experiments on the main and PFF subpayloads are sen-sitive to payload outgassing and steps need to be taken to keep outgassing to a minimum.These steps include proper material selection (see NASA Reference Publication 1124) andpayload cleanliness. Requirements for this payload are summarized below:

Machined parts should be thoroughly cleaned of all machining fluids and inks beforeinstallation.

Paper stick-on labels are not acceptable.

Acceptable materials include 3M Kapton tape (#92), DC340 Heat Sink Compound,no-wax lacing cord, GE RTV-11 potting compound, and Stycast 2850FT epoxy. Delrin,Teflon and Lexan are also acceptable.

Phenolic, PVC, and Nylon materials should be avoided.

Handling of the structure should be minimized to avoid greasy fingerprints.

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In addition, a dry nitrogen purge of the payload during integration and on the launcheris required. This minimizes the moisture absorption of the particle detectors. Once thenosecone is installed, the dry nitrogen purge is to be connected to the outside telemetry skinthrough a fly-a-way disconnect. A nitrogen purge is also needed for the camera coolingsystem.

Magnetic cleanliness: The 5 science magnetometers should be located as far as possiblefrom the batteries and high power circuits, and from any high-permeability metal. Magneticmaterials should not be used in the vicinity of the HE, HI, and Bagel particle detectors,because magnetic fields from these materials could affect the path of the charged particlesthat these instruments are sensing. Given the small volume of the PFFs, nonmagneticconnectors must be used throughout. On the main payload, nonmagnetic connectors areto be used in the forward deck structure; best effort to avoid magnetic materials near theSMILE sensor. The PFFs will be developed and evolved with measurements in the Wallopsmag cal facility.

RFI: If any DC-DC converters are used they must operate above 20 kHz.

15.0 Vehicle Performance

15.1 Minimum Altitude

Apogee between 700 and 800 km was requested. Nominal apogee is presently 639 km, giventhe payload definition at present. This is a reasonable compromise, but all efforts shouldcontinue to be made to minimize payload weight.

15.2 Coning Angle

Main and ACS: For the main payload, the coning should be driven to zero by the ACSprior to the subpayload ejections. After all deployments have taken place the ACS should nullthe coning and then be disabled for the remainder of the flight, since the payload is rigid (nofloppy booms.) A well-designed well-balanced payload will be essential. Creative placementof balance weights will be needed to maintain balance before and after deployments.

IMPORTANT NOTE re SUBPAYLOADS: The initial E-field subpayload coning half-angle must be less than 3 degrees immediately after ejection. All contributions to tip-offerror must be minimized to achieve a subpayload coning half-angle of less than 3 degreesimmediately after ejection. There will be no ACS on the subpayloads, and the followingguidelines should be followed to minimize the initial coning angle, and minimize the rate of

growth in the coning angle of the subpayloads. Dynamically balancing the subpayloads.

Designing the subpayload separation systems to minimize deployment asymmetries.

Arranging the components at the outside edges of each deck so that the roll momentof inertia is maximized, while keeping the payload as short as possible.

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Clustering the heaviest components (such as batteries) close to the C.G. so that thepitch moment of inertia is minimized.

PFFS: For the PFFs, minimal coning is also desired, but the electron detector has adeflectable aperture which can correct for cone angles and misalignment to B of up to 20degrees. Still, the PFF payloads should be designed to minimize coning as their sciencedepends on a stable rigid body motion (magnetometer analysis) and a magnetic-field-alignedview (electron detectors) within the view of the deflectable aperture. This will requiresensitive balancing of the PFF payloads, to within a few oz-in2.

15.3 Pointing and Payload Array Formation Requirements

The experiment consists of a main payload and four subpayloads, being two each of two kinds.The two identical E-field subpayloads will be separated by hundreds of meters in a linearconfiguration along the trajectory, and the two identical PFF subpayloads will be separatedperpendicular to the trajectory forming a triangle configuration with the main payload (see

Figure 1.) The PFF subpayloads should be ejected perpendicular to B with separationvelocity 1.5 m/s. The E-field subpayloads should be ejected forward and backward withthe apogee B-field vector with separation velocity 6-7 m/s. The spin vector of the mainpayload and the two E-Field subpayloads will be parallel to B. The main payload will havea helicopter geometry. These maneuvers require a gyro-based attitude control system.

The E-field subpayloads will be actively aligned only once, at deployment, antiparallelto apogee B. The main payload, however, will need to be aligned to within 6 deg of thelocal magnetic field throughout the science portion of the flight so that the imager is pointeddown the field line. To do this we will align to apogee-B after deployments; see Performancereport from NSROC for description.

There are a number of unusual restrictions on the pointing for this mission. An important

science goal will be studying the propagation of electric field waves along the magnetic fieldline from one E-field subpayload to another. Thus we wish to have, for a few hundred secondsabout apogee, the two E-field subpayloads on the same magnetic field line. Perfomancecalculations show that it is feasible to have the payloads magnetically conjugate to within100 m of the same field line for approximately 100 s near apogee, while the subpayloads aremore than 4 km separated along the field line. This requires that the E-field subpayloadsbe ejected, not along the local magnetic field line, but along a separation vector such thatat apogee they will be magnetically conjugate. Roughly, this means ejecting along a lineparallel to the apogee magnetic field vector.

The PFF payloads will form the perpendicular part of the array. Their exact positionsare not so restrictive, but they need to be (a) not too far away from the main (minimizesejection velocity) and (b) not forming a straight line with the main payload (means ejectionsare not symmetric).

15.4 Despin

After all deployments, a final main payload spin rate of exactly 1 Hz is needed to ensurepayload stability and achieve the scientific objectives. The camera places restrictions on theerror of this final roll rate.

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15.5 Attitude Control System

A gyro-based ACS is required on the main payload to satisfy the pointing, coning, and despinrequirements detailed in the previous 3 sections.

16.0 Range Support Dry nitrogen purge of payload (particle detectors) required during build-up and on

launcher.

Nitrogen purge for camera cooling system

Realtime display of magnetometer, all sky camera, MSP data from Poker Flat, andinternet access to realtime satellite data (ACE, GOES, etc.)

Realtime display of magnetometer, all sky camera, MSP, induction magnetometer datafrom Kaktovik.

Phone contact with Kaktovik.

Radar realtime data feed from Poker Flat to Kaktovik.

On-site generation of flight telemetry data on CD within one day of launch usingProgrammable Telemetry Processor (PTP) with data in PTP Stamp time format isrequested.

PFISR data

17.0 Launch Conditions Poker Flat Research Range winter Poker campaign, 2009

Before or near local magnetic midnight

Azimuth as close as possible to magnetic north

Solar illumination at apogee (desired)

Launch angle chosen for maximum apogee altitude

Launch requires: bright, active auroral display along the trajectory

real-time auroral imaging at the downrange site in Kaktovik

solar illumination of payloads at apogee (desired)

It is necessary to hold the count at T minus 2 minutes for up to 30 minutes at a time

Moon in last or first quarter or below horizon at Kaktovik

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18.0 Comprehensive Mission Success Criteria

Altitude: 639 km.

Main payload dynamics: Coning angle < 2.5 deg; ACS manuevers finished well before400 km; Spin rate 1 0.1 Hz; Angle between spin axis and B not greater than 6 degabove 200 km altitude.

E-field subs dynamics: Coning half angle not to exceed 20 deg during flight; Anglebetween spin axis and B not greater than 10 deg.

PFF dynamics: Coning half angle not to exceed 20 deg during flight; Angle betweencone center and B not greater than 7 deg.

Array formation: Two E-field subs magnetically conjugate within 100 m for at least 100sec about apogee while the E-field subpayload separation is at least 4 km; PFFs andmain payload forming an angle not more than 130 deg; PFF-main-PFF plane between

70 deg and 110 deg to B.

Instrument performance: 5 GPS providing location and timing; 2 E-field instrumentsproviding DC through HF data; 3 HEEPS e- providing synchronized data; 1 high-speedBagel providing field aligned electron data; 1 HEEPS ion providing ion distributionfunctions; 5 science magnetometers providing data that can be deconvolved to 1-2 nTaccuracy with 0.1 s time resolution; Imager providing data showing 400 m structure (5deg half angle field of view) at the payload magnetic footpoint throughout the flightabove 361 km altitude.

TM reception: All data received.

Ground data: Narrowfield imaging from Kaktovic tracking the payload footpoint; All-sky images provided from Poker and Kaktovic; PFISR data.

Science: Crossing of an active auroral arc system, with passage northward into thepolar cap; Alfvnic event recorded at polar cap edge; Alfven velocity measured byEfield subpayload delay and PFF perpendicular structure signature; Perpendicularshears recorded on upleg or downleg. Sunlight at apogee is highly desired.

19.0 Minimum Success Criteria

The parameters of minimum success are dependent on the performance analyses and tradeoffsbetween predicted performance and payload resources (weight, power.) The criteria belowwill need to be revisited as performance studies evolve.

Altitude: 557 km

Main payload dynamics: Coning angle


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E-field subs dynamics: Coning half angle not to exceed 45 deg during flight; initial coneless than 10 deg; Angle between spin axis and B not greater than 40 deg; initial angleless than 10 deg.

PFF dynamics: Coning half angle not to exceed 20 deg during science portion of flight;

Angle between cone center and B not greater than 10 deg during science portion offlight.

Array formation: Two E-field subs magnetically conjugate within 200 m for 100 secabout apogee while the E-field sub separation is at least 4 km; PFFs and main payloadforming an angle not more than 150 deg; PFF-main-PFF plane between 60 and 120deg to B.

Instrument performance: 1 E-field instruments providing DC and VLF data; Sciencedata received to allow a multiple-point field, particle, and image study of a dynamicauroral arc structure. This could consist of, as an example, the main payload, oneE-field sub, and one PFF providing GPS-positioned particle and field measurementsin the framework of image data from the ground or from the onboard camera.

TM reception: All data received with minimal dropouts.

Ground data: Narrowfield imaging from Kaktovic tracking the payload footpoint; All-sky images provided from Poker and Kaktovic. PFISR data...

Science: Crossing of an active auroral arc system, with passage northward into the polarcap; Alfvenic event recorded at polar cap edge; spatial/temporal structure discernedand measured.

20.0 Open Questions and Specific Concerns

Mechanical design of imager/ACS area; design of cascading baffle and its subpayloadmating; active cooling of imager sensor.

PFF TM and GPS re-rad issues

PFF and main payload balancing before/after deployments

PFISR interference

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21.0 List of Contacts

PI

--

Kristina LynchDepartment of Physics and Astronomy

Dartmouth College

(603) 646-9311

[email protected]

Co-Is

-------

Paul M. Kintner

302 Rhodes Hall

School of Electrical & Computer Engineering

Cornell University

Ithaca, NY 14853

(607) 255-5304

[email protected]

Marc Lessard

Institute for the Study of Earth, Oceans and Space


Durham, NH 03824

(603) 862-

[email protected]

Hans Stenbaek-NielsenGeophysics Institute

University of Alaska

[email protected]

John Bonnell

Space Sciences Laboratory

University of California, Berkeley

[email protected]

Chris Chaston

Space Sciences LaboratoryUniversity of California, Berkeley

[email protected]

Nickolay Ivchenko

Space and Plasma Physics

School of Electrical Engineering

KTH, Stockholm

[email protected]

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Goran Marklund



KTH, Stockholm

[email protected]

Craig Heinselman

SRI International

[email protected]

333 Ravenswood Ave. phone : (650)859-3777

Menlo Park, CA 94025-3493 fax : (650)322-2318

Engineering Design

---------------------------

Kevin G. Rhoads

Wilder 317A, HB 6127

Department of Physics and Astronomy

Dartmouth College

Hanover, NH 03755-3528

(603) 646-2972

[email protected]

Steven Powell

321 Rhodes Hall


Cornell University

Ithaca, NY 14853(607) 255-4551

[email protected]

Paul Riley



Durham, NH 03824

[email protected]

Mark Widholm

Space Science CenterMorse Hall


Durham, NH 03824

(603) 862-4597

[email protected]

David Collins

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Science Division Electronics Shop, 1A Wilder

Dartmouth College


(603) 646-3374

[email protected]

Ralph Gibson


Dartmouth College


(603) 646-3528

[email protected]

Goran Olsson



KTH, Stockholm

[email protected]

Monica Alaniz



KTH, Stockholm

[email protected]

Students

------------

Meghan MellaWilder 112, HB 6127


Dartmouth College


(603) 646-6416

[email protected]

Erik Lundberg

Rhodes Hall


Cornell UniversityIthaca, NY 14853

[email protected]

Sarah Jones



Durham, NH 03824

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[email protected]

Umair Siddiqui, Rachel Hochman, Parker Fagrelius, Claire McKenna

Wilder Lab HB 6127


Dartmouth CollegeHanover, NH 03755-3528

(603) 646-2972

[email protected]

Hanna Dahlgren



KTH, Stockholm

[email protected]

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Appendix A:

Cornell Instrumentation


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Appendix B:

Imager Instrumentation


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Appendix C:

SMILE Magnetometer Instrumentation


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Appendix D:

Dartmouth Instrumentation

cascades2 design review experimenters data

Documents