When spacecraft return to Earth, they don’t need to shed all their velocity by firing retro-rockets. Instead, they use the atmosphere as a brake to slow down for a soft landing. Every planet in the Solar System except Mercury has enough of an atmosphere to allow aerocapture maneuvers, and could allow high-speed exploration missions. A new paper looks at the different worlds and how a spacecraft must fly to take advantage of this “free lunch” to slow down at the destination.
As countries around the world respond to Russia’s invasion of Ukraine with sanctions aimed at crippling Moscow and Vladimir Putin, the global cooperation in space exploration that has been forged over the past 30-plus years will certainly be impacted.
The United Arab Emirates Space Agency releases a unique comprehensive Mars Atlas of the Red Planet.
You have never seen Mars like this. Recently, the New York University of Abu Dhabi (NYUAD) released an 88-page look at Red Planet, dubbed The Atlas of Mars. The Atlas is free online, and uses spectacular imagery taken from the United Arab Emirates Space Agency’s ambitious Mars Hope mission.
The CNSA (Chinese National Space Agency) has released an image of its Tianwen-1 spacecraft to coincide with the National Day and Mid-Autumn Festival. The spacecraft is on its way to Mars, and if the landing is successful, China will be only the third nation to successfully land a spacecraft on the planet.
NASA’s Mars 2020 Rover is heading to Mars soon to look for fossils. The ESA/Roscosmos ExoMars rover is heading to Mars in the same time-frame to carry out its own investigations into Martian habitability. To meet their mission objectives, the scientists working the missions will need to look at a lot of rocks and uncover and understand the clues those rocks hold.
To help those scientists prepare for the daunting task of analyzing and understanding Martian rocks from 160 million km (100 million miles) away, they’ve gone on a field trip to Australia to study stromatolites.
After months of setbacks, NASA says that the InSight Lander’s Mole is working again.
InSight landed on Mars on Nov. 26 2018 in Elysium Planitia. Its mission is to study the interior of the planet, to learn about how Mars and other rocky planets formed. InSight (Interior Exploration using Seismic Investigations, Geodesy, and Heat Transport) is a NASA mission with other partners, including the DLR (German Aerospace Center.)
NASA’s next mission to the surface of Mars is called the 2020 rover (in case you didn’t know already.) It’s planned launch date is July 17th, 2020, and it should land at Jezero Crater on Mars on February 18th 2021. The rover is still under construction at the Jet Propulsion Lab in Pasadena, California.
NASA’s Mars InSight Lander was always a bit of a tricky endeavour. The stationary lander has one chance to get things right, since it can’t move. While initially the mission went well, and the landing site looked good, the Mole is having trouble penetrating deep enough to fulfill its mission.
It may be the chance of a lifetime for planetary science.
This October, a comet will brush past a planet, giving scientists a chance to study how it possibly interacts with a planetary atmosphere.
The comet is C/2013 A1 Siding Spring, and the planet in question Mars. And although an impact of the comet on the surface of the Red Planet has long been ruled out, a paper in the May 2014 issue of Icarus raises the interesting possibility of possible interactions of the coma of A1 Siding Spring and the tenuous atmosphere of Mars. The study comes out of the Department of Planetary Sciences at the University of Arizona, the Belgian Institute for Space Aeronomy, the Institut de Planétologie et d’Astrophysique de Grenoble at the Université J. Fourier in France, and the Cooperative Institute for Research in Environmental Sciences at the University of Colorado in Boulder.
For the study, researchers considered how active Comet A1 Siding Spring may be at the time of closest approach on October 19th, 2014.
Discovered early last year by Robert McNaught from the Siding Spring Observatory in Australia, Comet A1 Siding Spring created a stir in the astronomical community when it was found that it will passextremely close to Mars later this year. Further measurements of its orbit have since ruled this possibility out, but its passage will still be a close one, with a nominal passage of 138,000 kilometres from Mars. That’s about one third the distance from Earth to the Moon, and 17 times closer than the nearest recorded passage of a comet to the Earth, Comet D/1770 L1 Lexell in 1780. Mars’ outer moon Deimos has an orbital distance of about 23,500 kilometres.
And although the nucleus will safely pass Mars, the brush with its extended atmosphere might just be detectable by the fleet of spacecraft and rovers in service around Mars. At a distance of 1.4 Astronomical Units (A.U.) from the Sun during the encounter, the vast coma is expected to be comprised primarily of H2O. At an input angle of about 60 degrees, penetration was calculated in the study to impinge down and altitude of 154 kilometres to the topside of the Martian ionosphere, in the middle of the thermosphere.
Such an effect should linger for just over 4 hours, well over the interaction period of Mars’ atmosphere with the coma of just over an hour, centered on 18:30 UT on October 19th, 2014.
What kind of views might missions like HiRISE and MSL get of the comet remains to be seen, although NEOWISE and Hubble are already monitoring the comet for enhanced activity. The Opportunity rover is also still functioning, and Mars Odyssey and ESA’s Mars Express are still in orbit around the Red Planet and sending back data. But perhaps the most interesting possibilities for observations of the event are still en route: India’s Mars Orbiter Mission and NASA’s MAVEN orbiter arrive just before the comet. MAVEN was designed to study the upper atmosphere of Mars, and carries an ion-neutral mass spectrometer (NGIMS) which could yield information on the interaction of the coma with the Martian upper atmosphere and ionosphere. The NGIMS cover is slated for release just two days before the comet encounter. All spacecraft orbiting Mars may feel the increased drag effects of the encounter.
Proposals for using Earth-based assets for further observations of the comet prior to the event in October are still pending. Amateur observers will be able to follow the approach telescopically, as Comet A1 Siding Spring is expected to reach +8th magnitude in October and pass 7’ from Mars in the constellation Ophiuchus as seen from the Earth. Mars just passed opposition last month, but both will be low to the south west at dusk for northern hemisphere observers in October.
It’s also interesting to consider the potential for interactions of the coma with the surfaces of the moons of Mars as well, though the net amount of water vapor expected to be deposited will not be large.
UPDATE: Check out this nifty interactive simulator which includes Comet A1 Siding Springs courtesy of the Solar System Scope:
The H2O coma of A1 Siding Spring is expected to have a radius of 150,000 kilometres when it passes Mars, just a shade over the nominal flyby distance.
“There is a more extended coma made up of H2O dissociation products (such as hydrogen and hydroxide) that extends for ~1,000,000 kilometres,” researcher at the Department of Planetary Sciences at the University of Arizona and lead author on the paper Roger Yelle told Universe Today.
“Essentially, Mars is in the outer reaches of the coma. The main ion tail misses Mars but there will be some ions from the comet that do reach Mars. The dust tail just misses Mars, which is fortunate.”
The paper also notes that significant perturbations of the upper atmosphere of Mars will occur if the cometary production rate is 10^28 s-1 or larger, which corresponds to about 300 kilograms per second.
“The MAVEN spacecraft will make very interesting observations,” Roger Yelle also told Universe Today. “The comet will perturb primarily the upper atmosphere of Mars and MAVEN was designed to study the upper atmosphere of Mars. Also, it’s just such an incredible coincidence that the comet arrives at Mars less than one month after MAVEN does. MAVEN is nominally in its checkout phase then, and the main science phase of the mission was not scheduled to start until November 1st. However, we are reassessing our plans to see what observations we can make. It’s all quite exciting, and we have to balance safety and the desire to make the best science measurements.”
It’s an unprecedented opportunity, that’s for sure… all eyes will be on the planet Mars and Comet A1 Siding Spring on October the 19th!
One of the big ticket astronomical events of 2014 will be the close passage of Comet C/2013 A1 Siding Spring past the planet Mars in October 2014. Discovered just over a year ago from the Australian-based Siding Spring Observatory, this comet generated a surge of excitement in the astronomical community when it was discovered that it was going to pass very close to the planet Mars in late 2014.
Now, a fleet of spacecraft are poised to study the comet in unprecedented detail. Some of the first space-based observations of the comet have been conducted by NASA’s Hubble Space Telescope and the recently reactivated NEOWISE mission. And although the comet may not look like much yet in the infrared eyes of NEOWISE, its estimated 4 kilometre in diameter nucleus is already active and shedding about 100 kilograms of dust per second.
And although an impact has been since ruled out, it’s that dust that may present a hazard for Mars orbiting spacecraft, as well as a unique scientific observing opportunity.
“Our plans for using spacecraft at Mars to observe Comet A1 Siding Spring will be coordinated with plans for how the orbiters will duck and cover, if we need to do so that,” said NASA/JPL Mars Exploration Program chief scientist Rich Zurek.
Comet A1 Siding Spring is projected to pass within just 138,000 kilometres of Mars on October 19th, 2014. This is one-third the Earth-Moon distance, and 10 times closer than the closest recorded passage of a comet by the Earth, which was Comet D/1770 Lexell in the late 18th century. The comet will also miss the Martian moons of Phobos and Deimos, which have the closest orbits of any moons in the solar system at just 5,989 and 20,063 kilometres above the surface of Mars, respectively.
Assets in orbit around the Red Planet are also slated to observe the close approach and passage of Comet A1 Siding Spring, as well as any extraterrestrial meteor shower that its dust may generate.
“We could learn about the nucleus – its shape, its rotation, whether some areas on its surface are darker than others,” Zurek said in a recent NASA/JPL press release.
The rovers Curiosity and Opportunity are currently active on the surface of Mars. Above in orbit, we’ve got the European Space Agency’s Mars Express, and NASA’s Mars Odyssey and the Mars Reconnaissance Orbiter (MRO). These will be joined by India’s Mars Orbiter Mission and NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft just weeks prior to the comet’s passage.
“A third aspect for investigation could be what effect the infalling particles have on the upper atmosphere of Mars,” Zurek said. “They might heat it and expand it, not unlike the effect of a global dust storm.”
Just last year, Mars based spacecraft caught sight of the ill-fated sungrazer Comet C/2012 S1 ISON as it passed Mars. But that dim passage yielded a scant pixel-sized view in the eyes of MRO’s HiRISE camera; Comet A1 Siding Spring will pass 80 times closer than Comet ISON and could yield a view of its nucleus dozens of pixels across.
Though the tenuous Martian atmosphere will shield to surface rovers from any micro-meteoroid impacts, they may also be witness to a surreptitious meteor shower from the debris shed by the comet, a first seen from the surface of another world.
But engineers will also be assessing the potential hazards that said particles may posed to spacecraft orbiting Mars as well.
“It’s way too early for us to know how much of a threat Siding Spring will be to our orbiters,” said JPL’s Mars Exploration Program chief engineer Soren Madsen recently. “It could go either way. It could be a huge deal or it could be nothing – or anything in between.”
In a worst case scenario, Mars orbiting spacecraft would be shuttered and oriented to “shelter in place” as the dust from the comet passes. There’s precedent for this in Earth orbit, as precious assets such as the Hubble Space Telescope were closed for business during the Leonid meteor storm of 1998.
“How active will Siding Spring be in April and May? We’ll be watching that,” Madsen continued. “But if the red alarm starts sounding in May, it would be too late to start planning how to respond. That’s why we’re doing what we’re doing right now.”
Comet A1 Siding Spring was the first comet discovered in 2013 at 7.2 Astronomical Units (AUs) distant. From our Earth based perspective, the comet will reach opposition on August 25th at 0.96 AU from the Earth, and approach 7’ from Mars on October 19th in the constellation Ophiuchus in evening skies. The comet reaches perihelion just 4 days later, and is slated to be a binocular comet around that time shining at magnitude +8.
The comet nucleus itself is moving in a retrograde orbit relative to Mars. Particles from A1 Siding Spring will slam into the atmosphere of Mars — and any spacecraft that happens to be in their way — at a velocity of 56 kilometres per second. For context, the recent January Quadrantids have a more sedate atmospheric impact velocity of 41 kilometres a second.
The unfolding 2014 drama of “Mars versus the Comet” will definitely be worth keeping an eye on… more to come!