NASA engineers are working on developing a star tracker at a low cost that would be able to locate stars during daylight hours.
According to a NASA statement, the team at NASA’s Wallops Flight Facility (WFF), located on Virginia’s Eastern Shore, is working on off-the-shelf solution to overcome the challenges of collecting data in daylight.
The star tracker is being developed specifically for the Wallops Arc Second Pointer (WASP) which would use the star tracker’s data to point a balloon-borne scientific payload with incredible accuracy and stability.
While WASP employs the commonly used ST5000 star tracker at present, this device cannot take images in the daytime even at 120,000 feet where scientific balloons operate.
“A precision attitude sensor capable of working in the daylight would extend scienceoperations through the day which would significantly increase the amount of science collected,” explained engineer Scott Heatwole.
Meanwhile the only precision attitude sensor available in daytime is a sun sensor at present. He noted, “This is not ideal because it provides only two axes of attitude and is not precise over a range of targets across the sky.”
According to Heatwole, his daytime star tracker consists of a commercial firewire camera attached to a lens and baffles that help filter out visible light, allowing it to sense points of reference in the near-infrared wavelength bands.
In 2014, a prototype of the device flew on two WASP missions. The first, the flight of the HyperSpectral Imager for Climate Science (HySICS) collected radiance data as WASP pointed the instrument toward the Earth, the sun, and the Moon. The goal was to see what the star tracker saw at 120,000 feet.
However, the second WASP mission, launched in October, carried the Observatory for Planetary Investigations from the Stratosphere (OPIS).
Its mission was to gather time measurements of Jupiter’s atmospheric structure, a challenge for the new star tracker because the gas giant is a bright object.
Meanwhile, the team plans to fine-tune the algorithms to eliminate the extra light experienced during the OPIS mission and then retest the technology during a sounding rocket flight this summer and additional WASP missions in 2016 and 2017.
“We’re trying to increase the capabilities of WASP,” Heatwole explained. “No company is going to go out and build this. No one is going to develop an off-the-shelf, low-cost daytime star tracker and put all the components in one package. WASP requires an attitude sensor that is capable in the daytime. That’s what we hope to create.”