Low Energy, Low Cost Swift A design experiment

1
Low Energy, Low Cost SwiftA design experiment

• June 2010

2
Mission Statement

• To 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.

3
Main Mission Requirements

• Source Localization 0.5
• Sky coverage as large as possible.
• Low Cost (lt 20M)
• Short Response Time (lt0.5 Hr)
• Mission duration gt 5 years

4
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.

5
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
6
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

7
Wide Field X-Ray Payload

• FOV 2 sr (89 x 89 deg)
• PSF lt17 arcmin
• Mass 20 kg
• Power 150 W
• Based on SWIFT BAT

8
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

9
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_at_16bit without
  compression

10
Orbit

• Dawn-Dusk sun-synchronous orbit
• Altitude 700 KM maybe higher to avoid debris
• Inclination 97 deg
• Orbit Benefits
• Constant sunlight (no eclipse)
• Constant thermal conditions
• Low radiation
• Similar to commercial earth observation satellite
  orbits (Cheaper launch opportunities)

11
Imaging Attitude

• Simple solution Non maneuvering satellite
• Payload always facing away from the sun
  (Efficiency 80)
• Complicated solution - maneuvering satellite
• Scan continuously all non-obstructed sky
• Requires secondary wide field UV payload

12
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

13
ROM pricing

• Hardware 7.5M
• Work 5.0M
• Total Price 12.5M