NASA papers guide search for extraterrestrial life

Network of scientists discuss search for biosignatures on exoplanets.

Five papers produced by a two-year interdisciplinary study on finding life beyond Earth provide guidelines on the search for extraterrestrial life in both our solar system and others.

Organized by NASA’s Nexus for Exoplanet System Science (NExSS), the papers include contributions by astrobiologists, planetary scientists, Earth scientists, heliophysicists, astrophysicists, chemists, and biologists.

Scientists with NASA’s Virtual Planetary Laboratory (VPL) at the University of Washington (UW) focused on a multidisciplinary approach to finding life beyond Earth.

“For life to be detectable on a distant world, it needs to strongly modify its planet in a way that we can detect. But for us to correctly recognize life’s impact, we also need to understand the planet and star–that environmental context is key,” noted Virginia Meadows of UW and principal investigator of VPL.

More than 3,700 exoplanets have been discovered since 1992. NExSS was created by NASA to draw from various scientific fields in searching for biosignatures, signs of extraterrestrial life.

A key accomplishment of NExSS has been facilitating communication between scientists searching for signs of microbial life on other solar system worlds and those looking for such signs on exoplanets.

The first of the papers, all published in the journal Astrobiology, identifies two types of signals scientists can use to search for life. One comes in the form of a planet’s atmospheric gases, such as oxygen, which can be produced by life ranging from microbes to plants. The other is through the type of light reflected by life forms, such as the colors of leaves.

These signatures can already be seen from Earth orbit. A new generation of telescopes, such as the James Webb Space Telescope (JWST), will let scientists probe exoplanets’ atmospheres.

In the second paper, researchers discuss “false positives” or signals that can erroneously lead scientists to conclude a planet has life, and “false negatives,” where signs of life could be missed. For example, oxygen can be produced by life as well as by non-living processes.

“There are lots of things in the universe that could potentially put two oxygen atoms together, not just photosyntheseis–let’s try to figure out what they are,” Meadows emphasized. “Under what conditions are they more likely to happen, and how can we avoid getting fooled?”

Understanding potential biosignatures is the focus of the third and fourth papers, in which researchers apply lessons learned from Earth to the exploration of other planets. Based on factors such as the chemistry in a planet’s atmosphere, a planet’s climate, and the presence of oceans and continents, scientists can assign a probability score as to whether that planet is likely to harbor life.

Biologists and geologists will have to work together to interpret findings about individual planets to determine whether life can adapt to their particular environments, explained Nancy Kiang, a VPL member and biometeorologist at NASA’s Goddard Institute for Space Studies in New York.

The fifth paper focuses on ground- and space-based telescopes, both current and future, that will be used to search for signs of life beyond Earth.

NASA selects first nine commercial crew astronauts

Scheduled for 2019, astronaut launches will be first from American soil, on American vehicles, since 2011.

Nine men and women have been selected by NASA to be the first astronauts to fly on commercial spaceflight vehicles built by Boeing and SpaceX.

Unofficially dubbed the “Commercial Crew Nine,” the group, whose names were announced by the space agency on Friday, August 3, consist of eight NASA astronauts and one who works for Boeing.

Their launches to the International Space Station (ISS) will be the first from US soil since the space shuttle program ended in 2011.

The astronauts were introduced in a public announcement made at NASA’s Johnson Space Center in Houston, Texas.

“This is a big deal for our country, and we want Americans to know that we are back. We’re flying American astronauts on American rockets from American soil,” said NASA Administrator Jim Bridenstine.

SpaceX’s Crew Dragon and Boeing’s CST-100 Starliner will each conduct two inaugural test flights to the ISS. For both companies, the first flights will be un-crewed. SpaceX’s Crew Dragon will launch on a Falcon 9 rocket while Boeing’s CST-100 Starliner will launch on a United Launch Alliance (ULA) Atlas V rocket. Both rockets are reusable.

Target dates for both the un-crewed and crewed launches remain uncertain. SpaceX hopes to launch the un-crewed mission in November of this year and the crewed one sometime next spring. Boeing’s schedule is similar, with the un-crewed launch now planned for either late 2018 or early 2019 and the crewed launch scheduled for mid-2019.

Both first flights were initially scheduled to launch in August 2018 and be followed by crewed launches later this year.

In 2014, NASA awarded SpaceX and Boeing contracts to fly astronauts to the ISS after the two companies won a competition that lasted four years.

One year later, the space agency announced that astronauts Bob Behnken, Eric Boe, Doug Hurley, and Sunita Williams were beginning training with SpaceX and Boeing.

Behnken and Hurley, both veteran NASA astronauts, will be the first to fly on the Crew Dragon, with launch currently scheduled for April 2019.

NASA astronauts Boe and Nicole Aunapu Mann and Boeing astronaut Chris Ferguson will be the first to fly on the Starliner.

Both the Crew Dragon and Starliner will fly two more missions after their crewed test flights. Veteran NASA astronaut Mike Hopkins and newcomer Victor Glover will fly on the next Crew Dragon mission while former ISS commander Williams and newcomer John Cassada will fly on the next Starliner mission.

Spanish telescope images meteorites impacting the Moon

Brief “flashes” caused by impacts on the Moon have been seen for at least 1,000 years.

The European Space Agency (ESA) has released images of two meteorites impacting the Moon in mid-July, captured by the Moon Impacts Detection and Analysis System (MIDAS) installed on three separate telescopes in Spain.

Equipped with high-resolution CCD video cameras, the lunar observing system was built to record the brief flashes, known as “transient lunar phenomena,” produced when meteorites hit the Moon.

“For at least a thousand years, people have claimed to witness short-lived phenomena occurring on the face of the Moon. By definition, these transient flashes are hard to study, and determining their cause remains a challenge,” the ESA noted in a public statement.

“For this reason, scientists are studying these ‘transient lunar phenomena’ with great interest, not only for what they can tell us about the Moon and its history, but also about Earth and its future.”

The meteorites that hit the Moon on July 17 and 18, less than 24 hours apart, were likely pieces of the Alpha Capricornids summer meteor shower, which originates from the tail of Comet 169P/NEAT, the ESA statement reported.

Each of the parent meteoroids were no larger than an average walnut, scientists estimate.

Studying meteorite impacts on the Moon helps scientists better understand such impacts on objects throughout the solar system.

“By studying meteoroids on the Moon, we can determine how many rocks impact it and how often, and from this, we can infer the chance of impacts on Earth,” said MIDAS member and meteorite specialist Jose Maria Madiedo of the University of Huelva in Spain.

“At MIDAS, we observe impacts on the ‘dark side’ of the Moon, meaning impact flashes stand out against the dark lunar ground.”

The Moon’s “dark side” is any lunar region not lit by the Sun at a given time and should be distinguished from its “far side,” which perpetually faces away from the Earth.

Video footage of both impacts is available for viewing on the ESA website.

Israel plans un-crewed Moon landing in 2019

Small, light craft scheduled for December launch on SpaceX rocket.

An Israeli non-profit organization, working in conjunction with a government-owned space corporation, plans to put a robotic lander on the Moon on February 13, 2019.

The joint project by SpaceIL and Israel Aerospace Industries (IAI) was initially intended for the Google Lunar X Prize competition, which Google ended March 31 with no winner after five teams experienced repeated launch delays, largely due to lack of funds.

Google had offered a $20 million prize to the first non-profit, privately-funded group to land a craft on the Moon, have it travel a minimum of 1,650 feet, and send high-definition photos and videos of the event back to Earth.

Like several of its competitors, including American teams Moon Express and Astrobotic, SpaceIL decided to continue pursuing the project without the prize. The non-profit has raised about $88 million in investments, largely from private donors, to develop and build its spacecraft.

Current plans call for SpaceIL’s lander to launch as a secondary payload on a SpaceX Falcon 9 rocket from Cape Canaveral, Florida, in December.

After launch, the lander will first enter into an elliptical orbit around the Earth. Once there, mission control will command it to raise itself to a much higher Earth orbit, also elliptical. From this location, it will approach the Moon, igniting its engines to enter lunar orbit before touching down on the lunar surface.

All of these tasks will be carried out autonomously through the lander’s navigation control system.

Weighing just 1,322 pounds (600 kilograms), the lander will be the lightest and smallest spacecraft to land on the Moon. If the landing is successful, the lander will follow up by using a magnetometer to measure the Moon’s magnetic field as well as take photos and videos.

Should the mission succeed, it will make Israel the fourth country to land a vehicle on the Moon’s surface, following Russia, the United States, and China.

Representatives of SpaceIL hope the project will inspire students to pursue careers in science, technology, engineering, and math, much like the Apollo program did during the 1960s and 1970s.