The ExoMars orbiter is preparing to make its first scientific observations at Mars during two orbits of the planet starting next week.
The Trace Gas Orbiter, or TGO, a joint endeavour between ESA and Roscosmos, arrived at Mars on 19 October. It entered orbit, as planned, on a highly elliptical path that takes it from between 230 and 310 km above the surface to around 98 000 km every 4.2 days.
The main science mission will only begin once it reaches a near-circular orbit about 400 km above the planet’s surface after a year of ‘aerobraking’ – using the atmosphere to gradually brake and change its orbit. Full science operations are expected to begin by March 2018.
But next week provides the science teams with a chance to calibrate their instruments and make the first test observations now the spacecraft is actually at Mars.
In fact, the neutron detector has been on for much of TGO’s cruise to Mars and is currently collecting data to continue calibrating the background flux and checking that nothing changed after the Schiaparelli module detached from the spacecraft.
It will measure the flow of neutrons from the martian surface, created by the impact of cosmic rays. The way in which they are emitted and their speed on arriving at TGO will tell scientists about the composition of the surface layer.
In particular, because even small quantities of hydrogen can cause a change in the neutron speed, the sensor will be able to seek out locations where ice or water may exist, within the planet’s top 1–2 m.
TGO’s first image of Mars – 13 June 2016. ESA.
The orbiter’s other three instruments have a number of test observations scheduled during 20–28 November.
During the primary science mission two instrument suites will make complementary measurements to take a detailed inventory of the atmosphere, particularly those gases that are present only in trace amounts.
Of high interest is methane, which on Earth is produced primarily by biological activity or geological processes such as some hydrothermal reactions.
The measurements will be carried out in different modes: pointing through the atmosphere towards the Sun, at the horizon at sunlight scattered by the atmosphere, and looking downwards at sunlight reflected from the surface. By looking at how the sunlight is influenced, scientists can analyse the atmospheric constituents.
In the upcoming orbits there are only opportunities for pointing towards the horizon or directly at the surface. This will allow the science teams to check the pointing of their instrument to best prepare for future measurements.
There is the possibility that they might detect some natural nightside airglow – an emission of light in the upper atmosphere produced when atoms broken apart by the solar wind recombine to form molecules, releasing energy in the form of light.
During the second orbit, the scientists have also planned observations of Phobos, the larger and innermost of the planet’s two moons.
Finally, the camera will take its first test images at Mars next week. In each of the two orbits, it will first point at stars to calibrate itself for measuring the planet’s surface reflectance.
Then it will point at Mars
Given the current elliptical orbit, the spacecraft will be both closer to and further from the planet than during its main science mission. Closest to the planet, it will be travelling faster over the surface than in its final circular orbit, which presents some challenges in timing when the images should be taken.
How TGO’s camera takes stereo images. Copyright University of Bern
The camera is designed to capture stereo pairs: it takes one image looking slightly forwards, and then the camera is rotated to look ‘back’ to take the second part of the image, in order to see the same region of the surface from two different angles. By combining the image pair, information about the relative heights of the surface features can be seen.
Next week, the camera team will be checking the internal timing to help programme commands for future specific scientific observations. The high speed and changing altitude of the elliptical orbit will make stereo reconstruction challenging, but the team will be able to test the stereo rotation mechanism and the various different camera filters, as well as how to compensate for spacecraft orientation with respect to the ground track.
There are no specific imaging targets in mind, although near the closest approach of the first orbit the orbiter will be flying over the Noctis Labyrinthus region and it will attempt to obtain a stereo pair. In the second orbit, it has the opportunity to capture images of Phobos.
Ultimately, the camera will be used to image and analyse features that may be related to the trace gas sources and sinks, to help better understand the range of processes that may be producing the gases. The images will also be used for looking at future landing sites.
“We’re excited we will finally see the instruments perform in the environment for which they were designed, and to see the first data coming back from Mars,” says Håkan Svedhem, ESA’s TGO Project Scientist.
After this brief science instrument demonstration period, which also serves as a test for relaying this data back to Earth, along with data from NASA’s Curiosity and Opportunity rovers, the focus turns back to operations and the preparations required to for aerobraking next year.
Understanding how fire spreads in a microgravity environment is critical to the safety of astronauts who live and work in space. And while NASA has conducted studies aboard the space shuttle and International Space Station, risks to the crew have forced these experiments to be limited in size and scope. Fire safety will be a critical element as NASA progresses on the journey to Mars and begins to investigate deep space habitats for long duration missions.
The first Spacecraft Fire Experiment (Saffire-I) was the beginning of a three-part experiment to be conducted over the course of three flights of Orbital ATK’s Cygnus vehicle to investigate large-scale flame spread and material flammability limits in long duration microgravity.
The Saffire-I experiment enclosure was approximately half a meter wide by 1 meter deep by 1.3 meter long and consisted of a flow duct and avionics bay. Inside the flow duct, the cotton-fiberglass blend burn sample measured 0.4 m wide by 1 meter long. When commanded by Orbital ATK and Saffire ground controllers operating from Dulles, Virginia, it was ignited by a hot wire. Previous to this experiment, the largest fire experiment that had been conducted in space is about the size of an index card.
After the experiment was ignited, the Cygnus continued to orbit Earth for six days as it transmitted high-resolution imagery and data from the Saffire experiment. Following complete data transmission, the Cygnus spacecraft completed its mission with a destructive entry into the Earth’s atmosphere.
Saffire-I launched inside the Cygnus spacecraft atop the United Launch Alliance (ULA) Atlas V launch vehicle on March 22, 2016. Space Station Crew members successfully grappled Cygnus to the space station on March 26. The Saffire experiments were developed at NASA Glenn Research Center by the Spacecraft Fire Safety Demonstration Project and sponsored by the Advanced Exploration Systems (AES) Division of NASA’s Human Exploration and Operations Mission Directorate. AES pioneers new approaches for rapidly developing prototype systems, demonstrating key capabilities, and validating operational concepts for future human missions beyond low-Earth orbit. AES activities are uniquely related to crew safety and mission operations in deep space, with a strong focus on future vehicle development.
Uranus is seen in this false-color view from NASA’s Hubble Space Telescope from August 2003. The brightness of the planet’s faint rings and dark moons has been enhanced for visibility. Credits: NASA/Erich Karkoschka (Univ. Arizona)
NASA’s Voyager 2 spacecraft flew by Uranus 30 years ago, but researchers are still making discoveries from the data it gathered then. A new study led by University of Idaho researchers suggests there could be two tiny, previously undiscovered moonlets orbiting near two of the planet’s rings.
Rob Chancia, a University of Idaho doctoral student, spotted key patterns in the rings while examining decades-old images of Uranus’ icy rings taken by Voyager 2 in 1986. He noticed the amount of ring material on the edge of the alpha ring — one of the brightest of Uranus’ multiple rings — varied periodically. A similar, even more promising pattern occurred in the same part of the neighboring beta ring.
“When you look at this pattern in different places around the ring, the wavelength is different — that points to something changing as you go around the ring. There’s something breaking the symmetry,” said Matt Hedman, an assistant professor of physics at the University of Idaho, who worked with Chancia to investigate the finding.
Chancia and Hedman are well-versed in the physics of planetary rings: both study Saturn’s rings using data from NASA’s Cassini spacecraft, which is currently orbiting Saturn. Data from Cassini have yielded new ideas about how rings behave, and a grant from NASA allowed Chancia and Hedman to examine Uranus data gathered by Voyager 2 in a new light. Specifically, they analyzed radio occultations — made when Voyager 2 sent radio waves through the rings to be detected back on Earth — and stellar occultations, made when the spacecraft measured the light of background stars shining through the rings, which helps reveal how much material they contain.
They found the pattern in Uranus’ rings was similar to moon-related structures in Saturn’s rings called moonlet wakes.
The researchers estimate the hypothesized moonlets in Uranus’ rings would be 2 to 9 miles (4 to 14 kilometers) in diameter — as small as some identified moons of Saturn, but smaller than any of Uranus’ known moons. Uranian moons are especially hard to spot because their surfaces are covered in dark material.
“We haven’t seen the moons yet, but the idea is the size of the moons needed to make these features is quite small, and they could have easily been missed,” Hedman said. “The Voyager images weren’t sensitive enough to easily see these moons.”
Hedman said their findings could help explain some characteristics of Uranus’ rings, which are strangely narrow compared to Saturn’s. The moonlets, if they exist, may be acting as “shepherd” moons, helping to keep the rings from spreading out. Two of Uranus’ 27 known moons, Ophelia and Cordelia, act as shepherds to Uranus’ epsilon ring.
“The problem of keeping rings narrow has been around since the discovery of the Uranian ring system in 1977 and has been worked on by many dynamicists over the years,” Chancia said. “I would be very pleased if these proposed moonlets turn out to be real and we can use them to approach a solution.”
Confirming whether or not the moonlets actually exist using telescope or spacecraft images will be left to other researchers, Chancia and Hedman said. They will continue examining patterns and structures in Uranus’ rings, helping uncover more of the planet’s many secrets.
“It’s exciting to see Voyager 2’s historic Uranus exploration still contributing new knowledge about the planets,” said Ed Stone, project scientist for Voyager, based at Caltech, Pasadena, California.
Voyager 2 and its twin, Voyager 1, were launched 16 days apart in 1977. Both spacecraft flew by Jupiter and Saturn, and Voyager 2 also flew by Uranus and Neptune. Voyager 2 is the longest continuously operated spacecraft. It is expected to enter interstellar space in a few years, joining Voyager 1, which crossed over in 2012. Though far past the planets, the mission continues to send back unprecedented observations of the space environment in the solar system, providing crucial information on the environment our spacecraft travel through as we explore farther and farther from home.
NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, built the twin Voyager spacecraft and operates them for the Heliophysics Division within NASA’s Science Mission Directorate in Washington.
For the first time in history, the U.S. government has approved a private company’s plans to visit the moon.
The lunar mission will be undertaken by Cape Canaveral, Florida-based Moon Express, Inc., an aerospace startup founded in 2010 by space entrepreneurs Dr. Robert (Bob) Richards, Naveen Jain and Dr. Barney Pell.
The landmark approval was given to Moon Express after meetings with the Federal Aviation Administration (FAA), the White House, the State Department NASA and other federal agencies.
The company plans to send a 20-pound, unmanned spacecraft beyond Earth’s orbit to the surface of the moon in 2017. If everything goes to plan, Moon Express will become only the fourth entity in history to soft-land on the moon following the U.S., USSR and China, as TechCrunch noted.
Jain enthusiastically described the ambitious moon-landing project to the Wall Street Journal:
If the maiden trip proves successful, the company plans to mine and retrieve rare elements and metals from the moon in future missions.
“This breakthrough U.S. policy decision provides authorization to Moon Express for a maiden flight of its robotic spacecraft onto the Moon’s surface, beginning a new era of ongoing commercial lunar exploration and discovery, unlocking the immense potential of the Moon’s valuable resources,” the venture’s press release states.
Unsurprisingly, this unprecedented commercial space mission opened up a can of interstellar worms—space regulation is under jurisdiction of the United Nations. As TechCrunch described, Moon Express bought its lunar craft from Rocket Lab on October 2015 before it even had government permission to launch it. The company also did not have the approval to keep what they find on the moon.
But then in November, President Obama signed the U.S. Commercial Space Launch Competitiveness Act into law that allows private companies to keep any resources taken from outer space.
Still, the company did not have clearance to make the trip. To get around this regulatory hurdle, according to TechCrunch, “Jain explained that representatives from multiple federal agencies, including the State Department and the NSA worked together to determine that the FAA, which is already responsible for granting launch licenses to rocket companies, should be the official point of contact for this type of activity.”
To get final government approval for the mission, Moon Express had to ensure it was not breaking space law, as The Verge explained:
Moon Express tried to address three critical provisions of the Outer Space Treaty. First, nations must continually supervise all of the space missions that happen within their borders. Moon Express told the FAA it would frequently update the agency with information on the 2017 trip, so that the government could oversee it.
The second rule is not messing with other nations’ spacecraft or space operations. On the Moon, that mostly means respecting the Apollo sites, and Moon Express assured the government that it wouldn’t disturb these areas.
“Don’t do wheelies over Neil’s footprint,” joked Richards.
Finally, Moon Express had to show the State Department it would abide by the Outer SpaceTreaty’s provision that is meant to prevent people from contaminating other worlds, called planetary protection. If companies like Moon Express want to land on a body in outer space, they have to be careful not to spread too many bacteria on the surface.
Fortunately the Moon doesn’t host life, so Moon Express doesn’t have to worry too much about contamination. In its voluntary disclosures to the federal government, Moon Express gave the FAA all its data about how it would adhere to the rules of planetary protection.
“The Moon Express 2017 mission approval is a landmark decision by the U.S government and a pathfinder for private sector commercial missions beyond the Earth’s orbit,” Richards said.
“We are now free to set sail as explorers to Earth’s eighth continent, the Moon, seeking new knowledge and resources to expand Earth’s economic sphere for the benefit of all humanity.”
“The sky is not the limit for Moon Express—it is the launchpad. This breakthrough ruling is another giant leap for humanity. Space travel is our only path forward to ensure our survival and create a limitless future for our children,” Jain said in the release.
“In the immediate future, we envision bringing precious resources, metals, and Moon rocks back to Earth. In 15 years, the Moon will be an important part of Earth’s economy, and potentially our second home. Imagine that.”
The company has a long-term mission of exploring and developing lunar resources for the benefit of humanity and a short-term mission of providing lunar transportation and services for government and commercial customers.
Moon Express hopes to win $30 million from the Google Lunar X-Prize to fuel their lunar mission.