June 19, 2021

UAE’s Hope orbiter on course for arrival at Mars


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Artist’s illustration of the Hope spacecraft at Mars. Credit: MBRSC

The first interplanetary probe from the United Arab Emirates is set to enter orbit around Mars on Tuesday, the first of three robotic missions taking aim on the Red Planet this month.

The Emirates Mars Mission spacecraft, also known as Hope or Al Amal, is set to begin a 27-minute firing of its six main thrusters around 10:30 a.m. EST (1530 GMT) Tuesday to slow down enough for Martian gravity to capture the probe into orbit.

If successful, the Hope orbiter will join spacecraft from NASA and the European Space Agency exploring Mars. But it is scheduled to receive company within days, with the scheduled arrival of China’s Tianwen 1 orbiter and rover Wednesday, and the landing of NASA’s nuclear-powered Perseverance rover Feb. 18.

The Hope, Tianwen 1, and Perseverance missions launched last July, rocketing into the solar system from spaceports in Japan, China, and Cape Canaveral. The trio of missions, all developed independently of one another, took advantage of a once-every-26-months alignment of Earth and Mars to permit the direct trip to the Red Planet.

The roughly $200 million Emirates Mars Mission is the Arab world’s first interplanetary probe. Engineers and scientists from the UAE partnered with U.S. researchers to develop the spacecraft and its three scientific instruments, all aimed at bringing into focus the structure and dynamics of the Martian atmosphere.

“Anything that you want to attempt to do in space is hard,” said Pete Withnell, program manager for the Emirates Mars Mission at the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder. “And something as sporty as getting a spacecraft into orbit around another planet is even harder.

“Many people may know the statistics,” Withnell said in a virtual press briefing in late January. “Less than half of those spacecraft that have been sent to Mars have actually made it successfully. So there are some statistics that are very sobering, but … this is a highly practiced, highly simulated, highly analyzed event on EMM. I cannot imagine being better prepared than we are right now. We are very fortunate to have a very healthy spacecraft, and everything is looking very good at the moment, so I’m optimistic.”

The Emirates Mars Mission launched July 19 from the Tanegashima Space Center in Japan, riding a Japanese H-2A rocket procured by the UAE government from Mitsubishi Heavy Industries. The H-2A hurled the 3,000-pound (1,350-kilogram) Hope spacecraft on a high-speed trajectory escaping the bonds of Earth’s gravity.

After deploying its solar panels and completing a post-launch checkout, the spacecraft fired its thrusters several times to adjust its course toward Mars, setting the stage for the critical Mars Orbit Insertion, or MOI, maneuver Tuesday.

“Right now, the team has prepared as well as they can possibly prepare to reach orbit around Mars,” said Sarah al-Amiri, the Mars mission’s lead scientist and the UAE’s minister of state for advanced sciences.

“It’s useful to first consider the fact that the Al Amal spacecraft is moving at exactly the right velocity to get it from Earth to Mars,” Withnell said. “Once it arrives at Mars, it’s moving too fast to get into the relatively small gravitational field of that planet. So the spacecraft has to slow itself down. If we do nothing, then the spacecraft will simply stay in an orbit about the sun, much like an asteroid.”

The Mars Orbit Insertion burn will cap a 307 million-mile (494 million-kilometer) interplanetary journey. At the current distance of Mars, it will take radio signals about 11 minutes to travel from the Hope spacecraft back to ground teams gathered at the Mohammed Bin Rashid Space Center in Dubai.

“So what the spacecraft principally needs to do is slow itself down,” Withnell said. “So a very short time prior to MOI, roughly an hour, the spacecraft will rotate. It has spent the vast majority of its time in the last seven months either pointing its solar arrays at the sun, or its antennas toward Earth… But neither of those orientations work for MOI.

“So we need to reorient the spacecraft so that the thrusters are pointed in the right direction, and they then burn for 27 minutes, and take out roughly 1,000 meters per second (2,236 mph) of velocity relative to Mars,” Withnell said. “And then we’re captured into into what is called a capture orbit about the planet. So fundamentally that’s what Mars Orbit Insertion is all about.”

The UAE’s Hope mission is on the home stretch of a 307 million-mile (494 million-kilometer) journey to Mars. Credit: MBRSC

The Mars Orbit Insertion Burn is a pivotal moment in the life of the Emirates Mars Mission, which the UAE government first announced in July 2014. Along with the launch, the MOI maneuver is one of the two riskiest parts of the mission, according to David Brain, deputy science lead on the mission from LASP.

“Of course, there’s some worry there, but overall I feel confident. I feel like the team has practiced, the spacecraft has been tested. There’s a chance that it might not go well, and we’ll deal with that when it happens,” Brain said. “Mostly, I’m feeling some anticipation, and like there is about to be a firehose of data headed my way.”

Navigators on Earth say the Hope spacecraft is right on target for the insertion burn. Hitting the aimpoint after the more than 200-day trip from Earth is comparable to an archer hitting 2-millimeter target from a kilometer away, Withnell said.

Ground controllers back on Earth will be in “observing mode” during the one-shot Mars arrival maneuver, according to Withnell.

“We have no opportunity to have any meaningful real time impact on what’s happening,” Withnell said. “So a lot of the engineering emphasis has been on making the MOI event completely autonomous, which of course means that the spacecraft needs to have some level of smarts on-board to take care of maybe some events that are not completely expected. So to some degree, the spacecraft can take care of itself. If a thruster fails and whatnot, then the spacecraft actually knows how to react to that. So during the event, we are observers, and we get to see what’s happening. But we do not interact in real time.”

Engineers will be watching telemetry streams from the spacecraft to confirm it is pointing in the right direction, and then verify that the burn started on time. Ground teams will monitor the Doppler shift in the radio signals from the spacecraft to measure how much it has slowed down relative to Mars, and the Hope probe itself will be calculating its trajectory autonomously.

Assuming the burn goes according to plan, the Hope spacecraft will swing into a preliminary capture orbit ranging between 600 miles and 30,700 miles (1,000-by-49,380 kilometers) from Mars. The science instruments will collect their first data at the Red Planet in the coming weeks, setting the stage for Hope to steer into an operational science orbit by mid-May that ranges between approximately 12,400 miles (20,000 kilometers) and 26,700 miles (43,000 kilometers) above Mars.

During parts of each 55-hour semi-synchronous orbit, the spacecraft’s move at roughly the same speed around Mars as the planet’s rotation. That will give the orbiter’s science instruments sustained views of the same region of Mars in much the same way weather satellites in geostationary orbit provide uninterrupted views of the same part of Earth.

In addition to the LASP facility in Colorado — where the spacecraft was built — and Dubai’s Mohammed Bin Rashid Space Center — where the probe will be operated — scientists from Arizona State University, the University of California, Berkeley, and Northern Arizona University contributed to the Hope mission.

The UAE’s government set the nation on a course for a Mars mission by outlining several objectives, including inspiration for Arab youth, revitalizing the UAE’s high-tech sector, introducing a culture for research and development, and aligning the mission’s arrival at Mars with the 50th anniversary of the country’s independence in 1971.

The Hope mission has already largely met those objectives, al-Amiri said.

The spacecraft was built for a fraction of the cost of NASA’s recent Mars orbiters, and still has the instrumentation necessary to investigate key unanswered questions about the Martian climate.

And the mission has gone a long way toward inspiring Arab youth, according to al-Amiri.

“Within a circle of people within the Arab region that I’m with, a lot of them are people that I’ve had discussions with even prior to the launch of this mission, and they were highly speculative with whether or not we will be able to achieve this objective,” she said. “And for them it’s been a reality check on what is possible from this region, and a reality check on how we can go about creating more and more positive change from the region. And I think a lot of the youth, especially over the course of at least the last six to seven years, have been really frustrated with instability and are looking for the creation of stability.

“Mars has been visible in the sky,” al-Amiri said. “Almost every child that I come into daily contact with … they’ll be able to point out Mars in the sky. I don’t think I’ve ever lived through a time where that was normal conversation in family settings.”

More than 450 people worked on the Emirates Mars Mission, according to UAE officials. About 200 members of the team have come from the UAE, and about 150 people from LASP in Colorado have worked on the project. Of the 200 Emiratis assigned to the mission, more than a third have been women.

This infographic illustrates the Hope mission’s journey to Mars. Credit: MBRSC

Brain said the instruments aboard the Hope spacecraft are similar to sensors flown on past space missions, but the UAE’s probe will go into a unique orbit that lingers higher above Mars.

The Emirates Mars Mission will put the instruments “into this new orbit that opens up all new science for us to investigate the Martian atmosphere,” Brain said. “So there are three aspects of the science orbit that are important. No. 1, it’s a very high altitude orbit, much higher than most other Mars science missions. That high-altitude orbit lets our instruments observe Mars from the global perspective. We’ll always be seeing roughly half of Mars, no matter where we are in the orbit when we look at the planet.

“No. 2, the orbit is fairly close to parallel with the Mars equator, and by this, I mean something like how the moon orbits Earth,” Brain said. “EMM will have a moon-like orbit around the planet unlike many other Mars spacecraft, which orbits over the top of the North Pole, and then over the bottom of the South Pole. They have highly inclined orbits that are very polar. Those kinds of orbits are great for science, but they force the spacecraft to always observe at the same time of day, 2 a.m., 2 p.m. 2 a.m., 2 p.m. When you lay that orbit on its side like the moon orbits the Earth, suddenly every time you go around the planet, you visit at every time of day. You get above midnight, you get above noon, you get above 3 p.m. You’ve seen all the times of day, which is great for our science.”

“The last part of the orbit that’s important here is that it still is elliptical. Sometimes the spacecraft is close to Mars, sometimes far from Mars,” Brain said. “So when it’s far from Mars, it’s moving slowly, it’s above one time of day, while Mars spins underneath. So it can observe many geographic regions at a single time of day. When the whole probe gets close to Mars it speeds up, and it can match the speed at which Mars is spinning on its axis. It can hover above a single geographic region like the big volcano Olympus Mons and study the atmosphere there at many times of day.”

Many of the science goals of the Emirates Mars Mission build on discoveries made by NASA’s Mars Atmosphere and Volatile Evolution, or MAVEN, which arrived at the Red Planet in 2014. Scientists have analyzed data from the MAVEN mission to confirm that the bombardment of the solar wind and radiation stripped away the Martian atmosphere, transforming the planet from a warmer, wetter world into the barren planet of today.

The Hope probe will track oxygen and hydrogen escaping from the Martian atmosphere into space, and will peer deeper into the planet’s atmosphere than MAVEN. Scientists want to investigate possible links between Martian weather and climate with the escape of atmospheric particles.

A color camera on the mission was developed by LASP at the University of Colorado at Boulder and MBRSC. Infrared and ultraviolet spectrometers were produced by LASP, Arizona State University and the University of California, Berkeley, in partnership with Emirati scientists.

“Overall, the science goal of EMM is to get a global understanding of sort of how the atmosphere works together, transport in the atmosphere, how weather above Olympus Mons influences weather completely on the other side of the planet, or at a different time,” Brain said.

“The first science objective is to understand the lower atmosphere of Mars in a global sense, and how the lower atmosphere of Mars varies geographically with time of day, and over the Martian seasons,” Brain said.

The Hope mission will also probe the outermost layers of the Martian atmosphere, where hydrogen and oxygen are escaping into space.

“We’ve learned from past missions that the loss of the atmosphere over time, over Martian history, we think, is important. But we need to do more to quantify that loss to understand how the rest of the atmosphere influences that loss to space,” Brain said.

The Hope spacecraft’s other primary science goal is to study the link between weather in the lower atmosphere and the conditions at the top of the atmosphere.

“If there’s a dust storm in the lower atmosphere, does atmospheric escape increase, and how?” Brain said. “If there is some change in the lower atmosphere, or a bunch of cloud formations, how does the upper atmosphere respond? In the past we’ve had missions that study the upper atmosphere, we’ve had missions to study the lower atmosphere, usually at just a single time of day, but we haven’t had a lot of observations that help us how understand how the atmosphere works from bottom to top, so EMM will provide that information.”

“We’re going to get complete coverage of the Martian atmosphere every nine Martian days, and by complete coverage, I mean we will have observed every geographic region at every time of day every nine days,” Brain said.

But first, the Hope spacecraft has to get itself into position to make those observations. That hinges on the Mars Orbit Insertion maneuver Tuesday.

What if something goes wrong?

“We continue on,” al-Amiri said. “It’s not a a one-off program. It is not something that you quit. We’ve had a taste of planetary exploration, and I think we will continue delving in for more.”

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Follow Stephen Clark on Twitter: @StephenClark1.


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