Tuesday, April 15, 2014

Satellite Games

ICE/ISEE3 International Cometary Explorer-International Sun Earth Explorer was launched in 1978 to explore the magnetosphere-solar wind interactions and repurposed in 1982 to visit Comet Giacobini-Zinner.  A reasonably close approach to Halley yielded more information, and like the little engine that could ICE was placed into a heliocentric orbit to monitor coronal ejections and cosmic rays.  ICE/ISEE3 was shut down in 1999.

Which brings us to today.  ICE is catching up with the earth and the carrier signal has been captured by amateurs.  The Planetary Society thinks that it can be recaptured and placed into the L1 Lagrangian point.  NASA wishes well, but is broke.  Keith Cowling and friends at NASA Watch and the Space College are trying to crowd source the new new mission but time is short, with commands to fire the on board rockets having to be sent in the next month or a bit more

Working in collaboration with NASA we have assembled a team of engineers, programmers, and scientists - and have a large radio telescope fully capable of contacting ISEE-3.  If we are successful we intend to facilitate the sharing and interpretation of all of the new data ISEE-3 sends back via crowd sourcing.

NASA has told us officially that there is no funding available to support an ISEE-3 effort - nor is this work a formal priority for the agency right now. But NASA does feel that the data that ISEE-3 could generate would have real value and that a crowd funded effort such as ours has real value as an education and public outreach activity.

Time is short. And this project is not without significant risks.  We need your financial help. ISEE-3 must be contacted in the next month or so and it must complete its orbit change maneuvers no later than mid-June 2014. There is excitement ahead as well: part of the maneuvers will include a flyby of the Moon at an altitude of less than 50 km.
In more space news, yesterday NASA  released a call for proposals to provide new and better data processing algorithms for Earth observation instruments on DSCOVR (aka GoreSat) which will sit out at L1 looking at the Sun and Earth.  As the bunnies may recall, DSCOVR rose from the dead because of the impending failure of ACE which was well past its due date and ailing, severely limiting space weather observation capabilities.
NASA has integrated two Earth - observing instruments, the Earth Polychromatic Imaging Camera (EPIC) and the National Institute of Standards and Technology (NIST) Advanced Radiometer (NISTAR) to the DSCOVR satellite. User guides and descriptions for these two instruments are available at http://avdc.gsfc.nasa.gov/pub/DSCOVR
Proposals are sought in two topical areas:

1. To develop and implement the necessary algorithms and processes to enable various data products from EPIC sunrise to sunset observations once on orbi(such as ozone or cloud maps),
as well as proposals to improve the calibrat ion of EPIC based on in - flight data;

2. To determine the Earth reflected and radiated irradiance with an accuracy of 1.5% or better from NISTAR, as well as proposals to improve the NISTAR calibrations based on in - flight data.
The short dates for the NOI and proposal indicate that a "pre-selection" might have occurred;) given that one would have to know a lot about the instruments to make a proposal.

Notices of Intent are requested by May 12, 2014; proposals are due July 14, 2014.
but the description of the instruments and their capabilities caught Eli's eye
EPIC images radiances from the sunlit face of the Earth on a 2048 x 2048 pixel CCD in 10 narrowband channels (ultraviolet [UV] and visible) with a nadir sampling field of view of approximately 8 km and an estimated resolvable size of 17 km for visible wavelengths. The 10 spectral bands, their Full Width at Half Maximum (FWHM), and some primary applications are:

Wavelength (nm)
Full Width (nm)
Primary Application
317.5 ± 0.1
1 ± 0.2
Ozone, SO2
325 ± 0.1
2 ± 0.2
340 ± 0.3
3 ± 0.6
Ozone, Aerosols
388 ± 0.3
 3 ± 0.6
Aerosols, Clouds
443 ± 1
3 ± 0.6
551 ± 1
3 ± 0.6
Aerosols, Vegetation
680 ± 0.2
2 ± 0.4
Aerosols, Vegetation, Clouds
687.75 ± 0.
2 0.8 ± 0.2
Cloud Height
764 ± 0.2
1 ± 0.2
Cloud Height
779.5 ± 0.
3 2 ± 0.4

Four pixels will be averaged onboard the spacecraft yielding downloaded images of 1024 x 1024 elements at an estimated resolvable size of 24 km. The time cadence of these spectral band images from EPIC will be provided on a best effort basis given existing ground system and network capabilities and will be no faster than 10 spectral band images every hour. The DSCOVR project will provide raw instrument data, EPIC Level-1 images in CCD counts that are geolocated and both dark-current and stray-light corrected. Calibration into radiances (Watts/m2/sr) will be given based on prelaunch calibration data. However, improvements in the Level-1 calibration, stray light, and dark current corrections are also solicited based on in-flight data imaging of Earth and the Moon.
The project will generate the "Earth from sunrise to sunset" Red-Green-Blue (RGB) images. This ROSES element is soliciting additional products from EPIC sunrise to sunset observations such as:
• Global ozone levels
• Aerosol index and aerosol optical depth
• Ultraviolet (UV) reflectivity of clouds over land and ocean
• Cloud height over land and ocean
• Cloud fraction
• Spectral surface reflectance
• Vegetation index and leaf area index
These measurements could contribute to assessing the utility for using L1 observations of Earth to integrate data from multiple spaceborne, as well as surface and airborne observation platforms, to develop self-consistent global products. Proposals are, therefore, sought to develop algorithms to provide other products of utility to the Earth science research and applications communities.
NISTAR measures the absolute "irradiance" as a single pixel integrated over the entire sunlit face of the Earth in four broadband channels:
1. A visible to far infrared (0.2 to 100 μm) channel to measure total radiant power in the UV, visible, and infrared wavelengths.
2. A solar (0.2 to 4 μm) channel to measure reflected solar radiance in the UV, visible, and near infrared wavelengths.
3. A near infrared (0.7 to 4 μm) channel to measure reflected infrared solar radiance.
4. A photodiode (0.3 to 1 μm) channel for calibration reference for the cavity radiometers.
Proposals are sought to determine the Earth reflected and radiated irradiance with an accuracy of 1.5% or better. Also, proposals to improve the NISTAR calibrations based on in-flight data are solicited.


Hank Roberts said...

I recall Gavin commenting that a corresponding satellite located at the midnight side will be needed to get energy balance information. Anyone doing that? I hope they're assuming it will happen and not leaving off any instrument that would be a part of a pair, eventually.

EliRabett said...

Basically they are using what they have access to, so it could be replicated.