SPRITE OBSERVATIONS DURING MEIDEX

Yoav Yair, Colin Price, Zev Levin and Adam Devir Department of Geophysics and Planetary Sciences, Tel Aviv University, Ramat Aviv, Israel

Upper End Plate w/ Quartz Window

Gimbal Motor & Worm Drive

Worm Gear

SEKAI WFOV Camera

Lower End Plate

Lens & Baffle

Xybion Camera

Avionics Mount Plate w/ electronics

Overall MEIDEX configuration

E-field response in Israel to sprite in the US.The positive initial field implies a positive lightning flash caused this sprite

VLF and ELF Antennas, Negev Desert, Israel

Dynamic Spectrum of VLF signal in Israel caused by sprite observed in the United States (horizontal

lines are VLF navigational transmitters)

Time (seconds)

0

10.5

Fre

quen

cy (

kHz)

12.5

0

Field of View for Sprite Observations

The Xybion IMC-201 camera has a rectangular FOV - 14.04(H) x 10.76 (V) degrees.This translates to a volume of 466 km (H) x 358 km (V) at the Earth’s limb, which is 1900km away from the shuttle.The spatial resolution is 665m (H) x 745m (V) per pixel.

The Sekai LL-Video color camera will be used to look for major thunderstorm centers. The FOV covers 2200 km of the horizon.

STS-107Space Shuttle Columbia OV-102Launch Date: May 23rd 2002Altitude: 150 NMDuration: 16 Days Crew: 7 Astronauts (double shift)

Main Regions of Interest: South-East AsiaJapan, Australia, South and North America, Africa

Payload

Xybion IMC- 201 radiometric CCD camera

• CCD Sensor: 756Hx581V

• Sensitivity - 10-6fc (~ 0.1 of typical night sky)

• Spectral range: 340-860nm

• 6 bands: 0.34, 0.38, 0.44, 0.56, 0.66, 0.86 nm

• Exposure Times: 50 nsec - 4 msec in 50 nsec steps

Wide Field Of View - Sekai White Light video camera

•60 degrees FOV

•3 Digital Sekai VCRs

During the Mediterranean Israeli Dust Experiment (MEIDEX) Earth-limb observations pointed above thunderstorms will be performed to record the optical emissions from TLEs (Transient Luminous Events - Sprites, ELVEs and Blue Jets). The 39 degrees inclination shuttle orbit covers the major lightning generating regions on Earth, increasing the probability of success in capturing these elusive discharges.

Optical observations from space

Primarily with the 665nm filter that matches the observed wide peak centered at 670nm, which typifies red spritesand with the 380 and 470nm filters to record blue jets.

Observational runs would consist of continuous recording of the Earth’s limb from the direction of the dusk terminator towards the night side, preferably before midnight local time at the observed area.

Thunderstorm activity predictions, based on Forecast Models will be up-linked daily to the shuttle, 24 hours prior to the observation.

The astronaut will have the ability to direct the camera toward areas of high lightning activity.

Ground Campaign

During the 16-day flight, two field sites in the Negev Desert in Israel will be used to collect data related to sprite activity in the ELF and VLF frequency range.

Additional ground stations in the USA, Brazil, Germany, Hungary, Japan, Taiwan, Antarctica will record and measure lightning and sprite activity.