First ASU-built space instrument ready for final lab tests

April 2, 2015

The first space instrument to be built at Arizona State University has just received the electronics it will use in flight. This starts the final laboratory tests leading to its launch next year on a NASA rocket.

The electronics for the OSIRIS-REx Thermal Emission Spectrometer, or OTES for short, arrived in a cleanroom at ASU's School of Earth and Space Exploration. The electronics are the final of three subsystems making up the instrument. The other two are the spectrometer's optical and mechanical systems. The first space-qualifed instrument to be built at ASU, OTES Download Full Image

On March 31, NASA gave a green light for the OSIRIS-REx mission to transition from development to bringing instruments and their components together. This will be followed in the months ahead by integrating and testing the spacecraft's combined systems.

The OSIRIS-REx mission will launch in September 2016 and fly to an asteroid, 101995 Bennu. There it will collect a sample of its rocks and dirt and bring them back to Earth in 2023. (OSIRIS-REx is short for Origins Spectral Interpretation Resource Identification Security Regolith Explorer; the University of Arizona in Tucson leads the mission.)

OTES plays a key part in the mission to Bennu. Its task is to use long-wavelength infrared light to map the asteroid's minerals, which will help mission scientists select where to collect samples. ASU is one of only a handful of universities in the United States capable of building NASA-certified space instruments.

"We have already built the spectrometer part of OTES and attached it to the telescope that collects light so it can work," said Philip Christensen, OTES' designer and principal investigator. Christensen is a Regents' Professor of geological sciences in SESE. "The final element is the electronics that will control the instrument. OTES has now received its brain and nervous system."

Next come tests as engineers working in a cleanroom in the Interdisciplinary Science and Technology Building 4 on the Tempe campus work to integrate the electronics with the optical and mechanical parts of OTES.

Testing will include placing OTES in a chamber where it is subjected to the same conditions it will experience during the mission. Aerospace engineers call this process "shake and bake" because it reproduces the vibrations of a rocket launch as well as the extremes of heat and cold that OTES must survive to do its job.

"NASA's rules for testing flight instruments and other space hardware are detailed and thorough," Christensen said. "They need to be. Once the spacecraft leaves Earth, there are no repair calls. Everything has to work perfectly."

Primitive target

Scientists chose asteroid Bennu as the target for the OSIRIS-REx mission because it has undergone relatively little change since it formed early in the solar system's history. Thus samples from Bennu may give us a better look at how the solar system formed.

With an orbit that brings it inside Earth's orbit, Bennu is the most accessible asteroid rich in organic materials. It is about 575 meters (1,900 feet) wide, roughly spherical and spins once every 4.3 hours. Reflecting only 3 percent of the sunlight falling on it, Bennu is about as dark as a charcoal briquette.

The flight plan calls for the OSIRIS-REx spacecraft to launch in September 2016 and rendezvous with Bennu in November 2019. It will spend up to 15 months surveying Bennu's mineralogy with OTES and another spectrometer working at shorter visible and infrared wavelengths. A suite of three visible-light cameras and a laser altimeter will draw a complete picture of the asteroid.

Mission scientists will then select a target area. The spacecraft will approach Bennu, touch it briefly and collect at least 60 grams (2 ounces) of dust, soil and rubble from its surface. Then OSIRIS-REx will cruise back to Earth and deliver the encapsulated sample to a landing site in Utah in September 2023. After dropping off the sample as it flies past Earth, the spacecraft may go on to survey other asteroids, although it will not be able to collect samples from them.

"As we put all its flight parts together and start on this final series of testing, it's very exciting to see OTES come to life in our hands," Christensen said.

The School of Earth and Space Exploration is an academic unit of the College of Liberal Arts and Sciences.

Robert Burnham

Science writer, School of Earth and Space Exploration


Giant balloon carrying ASU cameras invades Earth's stratosphere

April 3, 2015

It doesn’t take a sky-high budget to conduct aerospace research, thanks to weather balloons and a little ingenuity.

Teams of students from across Arizona, including a team from Arizona State University, launched their unmanned research balloons as part of the Arizona Space Grant Consortium’s ASCEND program, short for Aerospace Scholarships to Challenge and Educate New Discoverers. The launch took place March 27 in Pinal County West Park in Maricopa. ASCEND Download Full Image

Every semester student teams design and build payloads for launch on high-altitude weather balloons. About 10 feet in diameter when inflated, these hardy balloons can reach altitudes of more than 100,000 feet – higher than a passenger plane – yet can be built on a shoe-string budget.

This semester, a team of 12 ASU students put together a research payload to collect panoramic video and thermal imaging data. Instead of rockets, boosters and expensive control systems, they filled a weather balloon with hydrogen and hung a carbon fiber box underneath to carry the cameras and sensing equipment.

The balloon and camera made it up high enough to see the black sky curling around our blue planet, a staggering 94,687 feet. The flight was approximately three hours. When the balloon burst, the payload took about 45 minutes to come back to Earth, landing about 5.7 miles from the launch site.

ASU/NASA Space Grant provides funding to the ASU ASCEND team for payload materials and travel expenses. The payload cost roughly $1,000. The Arizona Near Space Research provides the balloons for the launch. Launch costs typically run around $5,000, including the “extras,” such as GPS beacons.

“As the team leader, I was required to manage the logistics of a complex project, making sure all systems work together in the final product. Having done this before, I have the opportunity to pass on the lessons I’ve learned to others on the team,” said Jack Lightholder, a paid ASU/NASA Space Grant intern and veteran balloon launcher.

Part of the Arizona Space Grant Consortium Workforce Development program, ASCEND is designed to engage undergraduate students in the full “design-build-fly-operate-analyze” cycle of a space mission.

“This program gives students the experience of developing an experimental question, developing a payload design to test it, building said payload and analyzing the data. The dataset will also be used for some baseline testing of other instruments within SESE labs,” Lightholder said. This was his seventh launch.

The ASCEND team is led by Tom Sharp, a professor in ASU’s School of Earth and Space Exploration and the Arizona Space Grant Consortium’s associate director. This year’s members include: Jack Lightholder, SG intern/team lead, computer science; Mason Denney, SG intern/team lead, computer systems engineering; Tyler McKinney, aerospace engineering; Ines Weber, physics; Clelia Tommi, astrobiology; Trevor Van Engelhoven, astrophysics; Vishal Ghorband, electrical engineering; Jefferson Fleing, aerospace engineering; Claeren Mapili, aerospace engineering; Zach Burnham, electrical engineering; John Gehrke, aerospace engineering; Mateo Orama, mechanical engineering.

Nikki Cassis

marketing and communications director, School of Earth and Space Exploration