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Emily LakdawallaDecember 27, 2017

What's Up in Solar System Exploration in 2018

2018 is shaping up to be a very busy year in space exploration, with most of the action happening relatively close to Earth. There will be three launches to the Moon and one each toward Mars and Mercury. Two spacecraft will rendezvous with near-Earth asteroids and prepare to descend for samples. We'll see the most distant ever planetary encounter with a tiny Kuiper belt object. And fifteen other spacecraft remain active in science missions at Venus, the Moon, Mars, Ceres, and Jupiter.

As far as human and commercial spaceflight are concerned, 2018 could be America’s biggest year in space since the shuttle program ended in 2011. Two sets of astronauts could launch from Florida in brand new spacecraft, and the most powerful rocket since the Saturn V is expected to come online. Meanwhile, 18 different astronauts are scheduled to fly on the ISS next year, not counting potential visiting commercial crews.

Robotic Launches

There are five planetary launches this year, of which three are headed to the Moon. The first is India's ambitious Chandrayaan-2 orbiter, lander, and rover, expected to launch in March. It's India's second lunar mission, far more ambitious than its first. China's Chang'e 4 mission will also take flight, with a relay orbiter launching to a halo orbit at the Moon-Earth L2 point in May or June. A separate launch will aim a lander and rover toward the first farside touchdown in November or December. I plan to have a blog entry about that mission posted here sometime in the next couple of months. The Chang'e 5 lunar sample return mission, originally scheduled for late 2018, will not launch until 2019 because of problems with the Long March 5 rocket. Also initially planned for 2018 was the Korea Pathfinder Lunar Orbiter, but it has been delayed to 2020.

A new Mars lander will head for the Red Planet this year: InSight is scheduled for launch May 5 and landing November 26 (the Monday after the Thanksgiving holiday). Unlike any previous planetary mission, its rocket (an Atlas V) will be launching from Vandenberg Air Force Base on the California coast, rather than Kennedy in Florida. The rocket has excess capacity to make up for Vandenberg's more northerly latitude, and launching from Vandenberg alleviates congestion at Kennedy.

It's technically not a planetary mission, but I can't wait for Parker Solar Probe, which will actually fly through the solar corona and sample it directly, which is just bananas. It will use repeated Venus flybys to drop its orbital perihelion close to the Sun. It is scheduled to launch from Kennedy Space Center aboard a Delta IV Heavy (a rocket that, famously, sets itself on fire during launch) between July 31 and August 19. If it launches on July 31, its first Venus flyby will be on September 28, and first perihelion on November 1.

Also headed toward the inner solar system next year is the ESA-JAXA mission to Mercury, BepiColombo. It will launch on an Ariane 5 from Kourou in a launch period that opens on October 5. BepiColombo has a lengthy journey ahead, including an Earth flyby in 2020, two Venus flybys in 2020 and 2012, and six Mercury flybys in 2021-2025 before Mercury orbit insertion on December 5, 2025.

Phew! That's a lotta launches. And that's just the robots. Jason Davis contributed the following updates on human and private spaceflight activities planned for 2018:

Human Spaceflight

SpaceX's new Crew Dragon is scheduled to make an uncrewed demo flight to the ISS in April 2018, followed by a crewed trip in August. Boeing aims to debut their Starliner capsule in August 2018, with a crewed trip to the ISS in November. The Government Accountability Office is skeptical of those timelines, warning both SpaceX and Boeing could face further delays, pushing crewed flights into 2019. 

SpaceX’s Falcon Heavy rocket, delayed since an earliest-predicted launch date of 2013, may finally be ready to fly. Space Launch Complex 40, which was damaged in a 2016 pad explosion, is operational again and launched an ISS resupply flight in mid-December. That allows SpaceX to finish modifying pad 39A for the Falcon Heavy, and should the Falcon Heavy’s first flight end catastrophically at liftoff, the company has a backup pad. CEO Elon Musk has downplayed expectations for the Falcon Heavy demo flight. At an ISS research and development conference in July, he said there is a moderate chance the flight will end in disaster. "I hope it makes it far enough away from the pad that it does not cause pad damage,” he said.

Should the demo mission fly successfully, the next two Falcon Heavy flights are STP-2 and Arabsat 6A, with STP-2 carrying Prox-1 and The Planetary Society’s LightSail 2 spacecraft into orbit as secondary payloads. The official launch date for STP-2 is no earlier than April 30, 2018—assuming the demo mission goes well.

2018 will be business as usual aboard the International Space Station—as much as that phrase applies to a continually occupied, microgravity laboratory circling the Earth every 90 minutes. Five crew expeditions will be in progress throughout the year, from Expeditions 54 to 58. Because of cost-saving measures by the Russian space agency Roscosmos, only seven out of 18 crew members aboard the ISS next year will be Russian. Eight are NASA astronauts, and the remaining three come from Japan, Europe and Canada’s space agencies.

Now let's check on all the ongoing missions, going from the innermost to outermost in the solar system. I count 18 missions operating as 2017 comes to a close. I spoke with representatives of several missions to get updates.


Akatsuki is, remarkably, still doing science at Venus. Unfortunately, two of its original five cameras are no longer functioning, but the rest continue to monitor Venus in ultraviolet and thermal infrared wavelengths, and the mission has been scientifically productive. It is expected to continue through 2018.

Parker Solar Probe will zoom past Venus in September.

The Moon

Like all of NASA's planetary missions that were granted extensions in 2016, Lunar Reconnaissance Orbiter is currently funded through all of 2018 and will next need to propose a further mission extension in 2019. Deputy project scientist Noah Petro told me that "LRO continues to operate nominally, with no significant degradation in the instruments or systems over the past several years. Our orbit is slowly evolving, though we’re still in an elliptical orbit with a perilune near the South Pole, with an average orbit of about 130 km by 60 km. This orbit allows us to conserve fuel in that it is stable over many years (i.e., we won’t hit the Moon!). Over the year we have a number of events and campaigns. We’ll watch both eclipses very carefully (January 31 and July 27) to see how the batteries respond to the extended periods of darkness. Each instrument has its own set of special observations [throughout the year]. During the larger meteor streams we look for evidence of exospheric enhancements in gases and dust, and the camera team searches for new impacts during favorable illumination conditions (beta angles between 30-60º [sun not too overhead or too low-angle]). We're looking forward to the next International Observe the Moon night in October."

As far as Andrew Jones and I can figure out, the Chang'e 3 lander and its ultraviolet telescope are still functioning on the lunar surface and will continue to do so into 2018.

According to project scientist David Sibeck, "the ARTEMIS spacecraft are all working perfectly well and we expect mission extension through 2020. Recent results include a determination of ULF wave growth rates in the Earth’s foreshock, far upstream from the Earth’s bow shock, using a radially-aligned spacecraft configuration. The two ARTEMIS spacecraft have also been used to determine how well the Earth’s magnetosphere and the Moon shield spacecraft and astronauts from solar energetic particles, a space weather hazard."

Near-Earth Asteroids

This summer will see two missions approaching their asteroid targets at nearly the same time. First, Hayabusa2 will be approaching asteroid Ryugu in July and is planned to do a soft landing in December. Second, OSIRIS-REx is approaching Bennu in August, and beginning its orbital mapping mission in October. The approach phases might yield cool pictures, but they might not; these are very tiny asteroids, so details won't be visible until the spacecraft are right on top of them. The two missions are aiming toward Earth sample return in December 2020 and September 2023, respectively.


There are eight, count them, eight active missions at Mars, and there should be one more on the surface before the year is out. As 2018 begins, we're approaching the middle of Mars Year 34, with Curiosity and Opportunity (which are both south of the equator) both experiencing some of the coldest temperatures of the year. The equinox comes on May 22, and southern summer solstice on October 16. The dust storm season is expected to begin after that, and it may be a dusty year.

The venerable 2001 Mars Odyssey is enjoying scientific results from its current orbit, in which it passes over the sunlit surface during very early morning. According to project scientist Jeff Plaut, they have no plans to change the orbit this year. THEMIS and the neutron detector are keeping busy. THEMIS has recently begun a Phobos observation campaign, which they plan to continue through 2018.

I asked Daniel Scuka at ESA for an update on Mars Express, and he assembled the following information from multiple mission sources: "MEX is in very good health having just exited from a challenging eclipse season. The season was challenging as it combined a perfect storm of long eclipses (up to 44 minutes), Mars being close to aphelion (so the spacecraft was heated less and received less power from the Sun via its solar arrays) and Solar Conjunction also occurred in the middle of the season which causes impedes the ability to command and receive telemetry from the spacecraft. It is difficult to estimate how much fuel remains as the uncertainties are large, but our best estimate (and hope) is that there is still enough fuel for several years' operations. The batteries are aging, but we estimate that they should last at least until the mid 2020s. The mission control team are now looking at ways to ensure attitude & orientation control in future as the 14-year-old gyros are showing signs of aging. Rosetta tested a 'gyroless' mode and the MEX team are looking to re-use the Rosetta mode on MEX to be able to switch off the gyros for much of the time and so prolong their life. There will be Phobos campaigns next year. In fact we will be changing the orbit very slightly in January 2018 to increase the frequency of Phobos flybys."

Opportunity is expected to continue moseying down Perseverance Valley on the rim of Endeavour throughout 2018, which will be its 15th year of Mars operations. Although it's winter, Opportunity has gotten through the lowest-energy period of the year and enjoyed some solar panel cleaning events that kept its panels productive.

Mars Reconnaissance Orbiter will shift its orbit slightly in order to be in place to cover InSight's November landing. As it did for Curiosity, it will record all the telemetry from the landing and play it back later. Its extended mission has it observing seasonal change with cameras and weather-observing spectrometer; the weather observations will also assist InSight's landing.

How Curiosity spends it year depends on whether they can get the drill working again. If they can, it will probably be parked for a fair amount of time in order to go through the challenging process of learning how to operate the drill and deliver samples in the new way. If they can't, Curiosity will drive, drive, drive. It's currently on top of Vera Rubin Ridge. The next place it will go is down off the ridge to the south into a region where Mars Reconnaissance Orbiter spotted clay minerals.

India's Mars Orbiter Mission is still going strong and has had its mission indefinitely extended. All its science instruments are still operating.

MAVEN continues to study Mars' atmosphere, and is doing so with increasing numbers of different observational modes for its instruments, according to principal investigator Bruce Jakosky. MAVEN operations will go through a substantial change after the end of its current mission extension: it will change its orbit to one that will be better for landed-mission relay, likely lowering the apoapsis. The new orbit will still permit great science, Jakosky says. He added that they are budgeting fuel with an eye toward maintaining operations through 2030 -- necessary because MAVEN may be the only NASA relay satellite available by the time Mars 2020 lands. (Let's all hope that Mars Reconnaissance Orbiter is still around then, though.)

ExoMars Trace Gas Orbiter should finish its aerobraking in March. Six weeks after, it will begin its primary science mission, planned to last through 2022. Six months after that, ExoMars will make its first data delivery to the Planetary Science Archive. The mission reached a milestone on November 16, when aerobraking safely brought ExoMars' apoapsis inside of Phobos' orbital distance (9320 kilometers above Mars' center). The team phased the orbit so that Phobos would be very nearly on the opposite side of Mars as ExoMars passed through the torus of space through which Phobos ever passes. They will perform regular data relay tests with NASA surface missions, and routine tandem atmosphere and particle observations with MAVEN. I'm looking forward to the gorgeous photos from CaSSIS!

Finally, as mentioned before, InSight lands in November!

Beyond Mars

Dawn has been approved for a second extended mission at Ceres, in which it will be adjusting its orbit to take it closer to Ceres than ever before, and it will observe seasonal change at the poles.

There will be seven Juno perijoves in 2018, beginning with PJ11 on February 7; PJ12 on April 1; PJ13 on May 24; PJ14 on July 16; PJ15 on September 7; PJ16 on October 29; and PJ17 on December 21. The evolution of Juno's orbit makes Juno's imaging opportunities with JunoCam progressively worse. They can no longer capture "marble movies" on approach or departure from perijove, but should continue getting good views of the poles throughout the year. The science instruments do not have this problem and will continue gathering quality data on the deep cloud structure, magnetic field, gravity, and charged particle environment around Jupiter all year.

After a long cruise, New Horizons will finally encounter its second Kuiper belt target, the diminutive 2014 MU69, on December 31. The tiny world will not be easy to spot on approach, and will probably only be resolvable as more than a point source of light for a brief few hours around the encounter. The spacecraft set the time of its MU69 flyby to 5:33 UT on January 1, 2019 with a successful rocket burn on December 9. For now, New Horizons is hibernating. It will wake up for the MU69 mission on June 4, and begin searching for the target with LORRI in August. Once it locates the target, navigators will plan a rocket burn to set the flyby altitude to 3500 kilometers. As 2018 comes to a close, New Horizons will begin searching for more moons or dust structures around MU69, which is already known to have at least one moon.

As always, I finish with amazement at Voyager 1 and 2, still traveling away from us, far beyond the Kuiper belt. NASA just successfully commanded Voyager 1 to use its backup thrusters for the first time in 37 years. Voyager 1 is 141 astronomical units from Earth, and slower Voyager 2 is at 117.

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Read more: InSight, Chandrayaan-2, mission status, Mars Express, Artemis, BepiColombo, Chang'E program, ExoMars TGO, Chang'e 3

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Emily Lakdawalla

Senior Editor and Planetary Evangelist for The Planetary Society
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