Low Energy, Low Cost SwiftA design experiment

June 2010

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Mission StatementTo detect and locate low energy X-ray bursts as precursors for supernova events, and to examine their time evolvement in the UV spectrum, using low cost space platform.

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Main Mission Requirements Source Localization: 0.5° Sky coverage: as large as possible. Low Cost: (< 20M$) Short Response Time: (<0.5 Hr) Mission duration: > 5 years

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Mission Concept Scan the sky using Wide Field Low Resolution

X-ray Telescope (WFLRXT). Use onboard processing to identify events,

excluding the milky way, sun and planets. Upon detection, maneuver and image the event

vicinity using the narrow field UV Telescope. Combine the two images (UV & X-ray) and

transmit it using satellite phone/internet to designated destinations.

Alert all Hi-Res narrow FOV telescopes, and keep imaging using the UV telescope.

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Designated Bus IMPS* 2 BUS (used by TECSAR & Venμs

satellites). Onboard processor: LEON-3 Power Supply: 800W Bus Power Consumption: 250W Battery Capacity: 30 Ah Bus Dry Mass: 190 Kg Payload Mass: ≤150 Kg*IMPS = Israeli Multi Purpose Satellite

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BUS – AOCS system Actuators:

4 reaction wheels (1 spare) – fine pointing 2 X 3 axis magento-torquers– momentum unloading Hydrazine Thrusters

Sensors: 2 sun-sensors 2 magneto-meters MEMS coarse rate gyro GPS Receiver

Propulsion System (for orbit control): Hydrazine Thrusters

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Wide Field X-Ray Payload FOV: 2 sr (89 x 89 deg) PSF: <17 arcmin Mass: 20 kg Power: 150 W

*Based on SWIFT – BAT

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Narrow Field UV payload Ultra Violet Optical Telescope, 3 deg field

170 to 650 nm wavelengths*

30 cm aperture

500X500 detector (or larger)

Power: 150 W

FOV: 3 deg

Resolution: 0.01 deg

A/D: 16 bit

*Based on SWIFT – UVOT

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Data Storage and Transmission LEON3 On Board Computer (2 GBytes)

More than 100 UV images 30 images for the first 30 minutes 48 images for the next 24 hours 16 images for the last 24 hours

TDRSS datalink (10Mbits/sec)0.4 sec for image

Satellite Phone (50 Kbit/sec)80 sec for image

*image size: 4Mbits = 500x500@16bit without compression

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Orbit Dawn-Dusk sun-synchronous orbit

Altitude: 700 KM maybe higher to avoid debris Inclination: 97 deg

Orbit BenefitsConstant sunlight (no eclipse)Constant thermal conditionsLow radiationSimilar to commercial earth observation

satellite orbits (Cheaper launch opportunities)

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Imaging Attitude Simple solution – Non maneuvering

satellitePayload always facing away from the sun

(Efficiency: 80%) Complicated solution - maneuvering

satelliteScan continuously all non-obstructed skyRequires secondary wide field UV payload

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On-board Processing Masking out unwanted regions within the

FOV (i.e. Milky way, sun and planets) Merging UV and X-ray images upon

detection

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ROM pricing Hardware 7.5M$ Work 5.0M$ Total Price 12.5M$