Assembly of Mars rover’s rocket to begin this week

-Das Stapeln der Atlas 5-Rakete – Hecknummer AV-088 – soll am 28. Mai mit dem Heben der Vertikalen der ersten Stufe auf der mobilen Startplattform von Atlas innerhalb des VIF beginnen, so Omar Baez, Startdirektor der NASA für die Ausdauer Rover Mission.

-ULA wird die vier Booster des Atlas 5 mit festem Brennstoff installieren, nachdem die erste Stufe im vertikalen Hangar der Rakete angehoben wurde.

-Die Centaur-Oberstufe des Atlas 5, die den Rover auf einer Fluchtbahn von der Erde weg treiben wird, wird um den 4. Juni auf der Rakete gestapelt, sagte Baez.

-ULA wird die Atlas 5-Rakete am 17. Juni für einen Betankungstest auf Pad 41 ausrollen. ULA führt solche Betankungsdemonstrationen vor dem Start mit begrenzten Startfenstern für Planeten durch, um sicherzustellen, dass Teams Probleme mit der Rakete vor dem Starttag erkennen und lösen können.

-„Nachdem wir damit fertig sind, werden wir das Rover-Raumschiff am 22. Juni mit dem Atlas-Zentauren verbinden, einen Test zwischen ihm und der Rakete durchführen, und das wird uns so ziemlich auf unsere endgültigen Überprüfungen und die Installation von vorbereiten die RTG, die eine Generalprobe durchführt und unsere Überprüfung der Startbereitschaft aus dem Weg räumt “, sagte Baez in einem Interview mit Spaceflight Now.

Wrapped up for shipment, the first stage of the Atlas 5 rocket that will launch NASA’s Perseverance rover arrived at Cape Canaveral one May 18 aboard a Ukrainian-built Antonov An-124 cargo plane. Credit: NASA/Kim Shiflett

Two key pieces of hardware needed for NASA’s next Mars rover — an Atlas rocket booster and sterile components of the rover’s sample collection system — recently arrived at Cape Canaveral ahead of the mission’s scheduled launch July 17.

The first stage of United Launch Alliance’s Atlas 5 rocket arrived at Cape Canaveral Air Force Station’s Skid Strip runway May 18 aboard a Ukrainian-built Antonov An-124 transport plane. The cargo aircraft carried the 107-f0ot-long (32-meter) Atlas first stage from Huntsville, Alabama, near ULA’s rocket factory in Decatur.

After unloading the booster from the cargo jet, ULA moved the rocket into the Atlas Spaceflight Operations Center for post-shipment checks.

ULA typically delivers rocket hardware launch sites using the company’s ocean-going vessel named “RocketShip.” But the vessel recently ferried there Delta 4 rocket cores to Vandenberg Air Force Base in California, and was not available for the Atlas 5 shipment to Florida.

Rocket and rover preparations for the July launch are continuing with safeguards to mitigate impacts from the coronavirus pandemic.

Omar Baez, NASA’s launch director for the Perseverance mission, said the rocket’s arrival at Cape Canaveral and the successful launch of the previous Atlas 5 flight May 17 “should set us up with plenty of time for hitting the beginning of the (rover) launch window July 17.”

“Things are progressing as well as they can,” Baez said.

Liftoff is scheduled at 9:10 a.m. EDT (1310 GMT) on July 17, within a broader window extending from 9:00-10:40 a.m. EDT (1300-1440 GMT), according to Baez.

“We’re really looking forward to this one,” he said. “Things evolve from day-to-day. We learn from every mission as far as things that we have to do to protect ourselves and to prevent the team from getting sick.

“We’re definitely are encouraging people, unless they have a significant primary role, not to travel for the testing or the launch,” Baez said. “That work is progressing as best we can. Obviously, there’s a lot of teleworking, but when we do have to have the hands-on work, we try to do it in as safe of a manner as possible.”

Hardware for the Perseverance rover landed at the Kennedy Space Center’s Launch and Landing Facility on May 11 on a NASA C-130 transport plane. The delivery included the mission’s sample tubes, cigar-sized metal cylinders that will store rock samples collected by the Perseverance rover for retrieval and return to Earth by subsequent robotic missions.

The two hardware arrivals signaled the start of a new phase of launch preparations for the Perseverance rover, the centerpiece of NASA’s $2.5 billion Mars 2020 mission.

The 43 sampling tubes are part of the rover’s sample handling system, consisting of a robotic arm, motors, seals and a rotating array of nine drill bits for abrading, regolith collection, and coring of Martian rocks. The specimens drilled from rocks will be stored into the metallic tubes, where samples will be hermetically sealed to await arrival of a follow-on robotic mission in the late 2020s, which will return the material to Earth for analysis.

Workers offload the Perseverance rovers’ Adaptive Caching Assembly May 11 from a NASA C-130 cargo plane at Kennedy Space Center’s Launch and Landing Facility. Credit: NASA/Ben Smegelsky

The Perseverance rover is inside the Payload Hazardous Servicing Facility at Kennedy, where ground teams are putting the final touches on the spacecraft before its closed up inside the payload fairing of its Atlas 5 launcher.

With the final pieces of the sampling system now at Kennedy, NASA teams planned to finish installing the mission’s heat shield. Other tasks planned in the next few weeks include fueling of the mission’s cruise stage, which will shepherd the rover during the seven-month journey from Earth to Mars.

The rover — enclosed inside its atmospheric entry capsule — will then be mated with the cruise stage and attached to the Atlas 5’s payload attachment fixture. The entire spacecraft will next be encapsulated inside the Atlas 5’s Swiss-made payload fairing, then transferred to ULA’s Vertical Integration Facility for integration with the launch vehicle.

Stacking of the Atlas 5 rocket — tail number AV-088 — is scheduled to get underway May 28 with the hoisting of the first stage vertical on top of the Atlas mobile launch platform inside the VIF, according to Omar Baez, NASA’s launch director for the Perseverance rover mission.

ULA ground crews transferred the mobile launch platform back inside the VIF from Cape Canaveral’s Complex 41 launch pad last week following liftoff of the previous Atlas 5 flight May 17.

The Atlas 5 for the Perseverance rover mission will fly in the “541” configuration with four strap-on solid rocket boosters and a 17.7-foot-diameter (5.4-meter) diameter payload fairing.

ULA will install the Atlas 5’s four solid-fueled boosters after raising the first stage inside the rocket’s vertical hangar.

The Atlas 5’s Centaur upper stage, which will propel the rover on an escape trajectory away from Earth, will be stacked on top of the rocket around June 4, Baez said.

NASA’s Perseverance rover is seen mounted on its descent stage inside the mission’s atmospheric entry vehicle, which will protect the rover when it plunges into the Martian atmosphere. Credit: NASA/Christian Mangano

ULA will roll the Atlas 5 rocket out to pad 41 on June 17 for a fueling test. ULA performs such fueling demonstrations before launches with limited planetary launch windows to ensure teams can detect and resolve any problems one the rocket before launch day.

The Atlas 5 will return to the VIF after the tanking test.

“After we’re done with that, we’ll mate the rover spacecraft to the Atlas-Centaur on June 22, do a test between it and the rocket, and that’ll set us up pretty much for our final reviews, installation of the RTG, doing a dress rehearsal, and getting our launch readiness review out of the way,” Baez said in an interview with Spaceflight Now.

The Multi-Mission Radioisotope Thermoelectric Generator, or MMRTG, is the rover’s nuclear power source. The device converts heat from the radioactive decay of plutonium into electricity. Provided by the U.S. Department of Energy, the power generator is one of the final items installed on the rover in the final weeks before launch.

The Atlas 5 rocket is the only launch vehicle currently certified by NASA to carry nuclear-powered payloads into space.

The rocket assigned to the Perseverance rover launch has no significant modifications from ULA’s standard Atlas 5 vehicle, Baez said.

But there’s one change to the pyrotechnic system that would be activated to destroy the Atlas 5 if it deviates from its planned course and threatens populated areas. Such an event is highly unlikely, and the Atlas 5 has successfully reached orbit on all 84 of its missions to date.

“If you did have some kind of accident, that’s to prevent the MMRTG from being a danger to the public,” Baez said. “So we try to be very precise in destroying, for example the Centaur (upper stage), in a way that the MMRTG is not in harms way, where it could harm the public. Thats about the only difference between this and a non-nuclear mission.”

Baez said the same type of ordnance system was used on the Atlas 5 rocket that launched the Curiosity Mars rover in 2011. The Perseverance rover is similar in design to Curiosity, but carries a different set of scientific instruments.

The Perseverance rover’s launch window extends from July 17 through Aug. 11. NASA and ULA recently assessed the performance of the Atlas 5 rocket and the final mass of the spacecraft, engineers determined they could add six days to the launch period.

Launch opportunities to Mars only come about once every 26 months, when the positions of the planets make a direct journey possible.


Astrobiology: The Detective Aboard NASA’s Perseverance Rover

This artist's concept depicts NASA's Mars 2020 rover exploring Mars.
SHERLOC on Perseverance’s Robotic ArmSHERLOC, one of the instruments onboard NASA’s Perseverance Mars rover, sits on the end of the rover’s robotic arm. Credits: NASA/JPL-Caltech. Full image and caption ›

An instrument called SHERLOC will, with the help of its partner WATSON, hunt for signs of ancient life by detecting organic molecules and minerals.

Mars is a long way from 221B Baker Street, but one of fiction’s best-known detectives will be represented on the Red Planet after NASA’s Perseverance rover touches down on Feb. 18, 2021. SHERLOC, an instrument on the end of the rover’s robotic arm, will hunt for sand-grain-sized clues in Martian rocks while working in tandem with WATSON, a camera that will take close-up pictures of rock textures. Together, they will study rock surfaces, mapping out the presence of certain minerals and organic molecules, which are the carbon-based building blocks of life on Earth.

SHERLOC was built at NASA’s Jet Propulsion Laboratory in Southern California, which leads the Perseverance mission; WATSON was built at Malin Space Science Systems in San Diego. For the most promising rocks, the Perseverance team will command the rover to take half-inch-wide core samples, store and seal them in metal tubes, and deposit them on the surface of Mars so that a future mission can return them to Earth for more detailed study.

SHERLOC will be working with six other instruments aboard Perseverance to give us a clearer understanding of Mars. It’s even helping the effort to create spacesuits that will hold up in the Martian environment when humans set foot on the Red Planet. Here’s a closer look.

Mars 2020's SHERLOC Instrument
Mars 2020’s SHERLOC Instrument: An engineering model of SHERLOC, one the instruments onboard NASA’s Perseverance Mars rover. Located on the end of the rover’s robotic arm, SHERLOC will help determine which samples to take so that they can be sealed in metal tubes and left on the Martian surface for future return to Earth. Credits: NASA/JPL-Caltech. Full image and caption ›

The Power of Raman

SHERLOC’s full name is a mouthful: Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals. „Raman“ refers to Raman spectroscopy, a scientific technique named after the Indian physicist C.V. Raman, who discovered the light-scattering effect in the 1920s.

„While traveling by ship, he was trying to discover why the color of the sea was blue,“ said Luther Beegle of JPL, SHERLOC’s principal investigator. „He realized if you shine a light beam on a surface, it can change the wavelength of scattered light depending on the materials in that surface. „

This effect is called Raman scattering. Scientists can identify different molecules based on the distinctive spectral „fingerprint“ visible in their emitted light. An ultraviolet laser that is part of SHERLOC will allow the team to classify organics and minerals present in a rock and understand the environment in which the rock formed. Salty water, for example, can result in the formation of different minerals than fresh water. The team will also be looking for astrobiology clues in the form of organic molecules, which among other things, serve as potential biosignatures, demonstrating the presence life in Mars‘ ancient past.

„Life is clumpy,“ Beegle said. „If we see organics clumping together on one part of a rock, it might be a sign that microbes thrived there in the past.“

Nonbiological processes can also form organics, so detecting the compounds isn’t a sure sign that life formed on Mars. But organics are crucial to understanding whether the ancient environment could have supported life.

A Martian Magnifying Glass

Mineral Map Created During a Test of SHERLOC
Mineral Map Created During a Test of SHERLOC: In this test image by SHERLOC, an instrument aboard NASA’s Perseverance rover, each color represents a different mineral detected on a rock’s surface. Credits: NASA/JPL-Caltech. Download image ›

When Beegle and his team spot an interesting rock, they’ll scan a quarter-sized area of it with SHERLOC’s laser to tease out the mineral composition and whether organic compounds are present. Then WATSON (Wide Angle Topographic Sensor for Operations and eNgineering) will take close-up images of the sample. It can snap images of Perseverance, too, just as NASA’s Curiosity rover uses the same camera — called the Mars Hand Lens Imager on that vehicle — for science and for taking selfies.

But combined with SHERLOC, WATSON can do even more: The team can precisely map SHERLOC’s findings over WATSON’s images to help reveal how different mineral layers formed and overlap. They can also combine the mineral maps with data from other instruments — among them, PIXL (Planetary Instrument for X-ray Lithochemistry) on Perseverance’s robotic arm — to see whether a rock could hold signs of fossilized microbial life.

Meteorites and Spacesuits

Any science instrument exposed to the Martian environment for long enough is bound to change, either from the extreme temperature swings or the radiation from the Sun and cosmic rays. Scientists occasionally have to calibrate these instruments, which they do by measuring their readings against calibration targets — essentially, objects with known properties selected in advance for cross-checking purposes. (For instance, a penny serves as one calibration target aboard Curiosity.) Since they know in advance what the readings should be when an instrument is working correctly, scientists can make adjustments accordingly.

About the size of a smartphone, SHERLOC’s calibration target includes 10 objects, including a sample of a Martian meteorite that traveled to Earth and was found in the Oman desert in 1999. Studying how this meteorite fragment changes over the course of the mission will help scientists understand the chemical interactions between the planet’s surface and its atmosphere. SuperCam, another instrument aboard Perseverance, has a piece of Martian meteorite on its calibration target as well.

While scientists are returning fragments of Mars back to the surface of the Red Planet to further their studies, they’re counting on Perserverance to gather dozens of rock and soil samples for future return to Earth. The samples the rover collects will be exhaustively studied, with data taken from the landscape in which they formed, and they’ll include different rock types than the meteorites.

Next to the Martian meteorite are five samples of spacesuit fabric and helmet material developed by NASA’s Johnson Space Center. SHERLOC will take readings of these materials as they change in the Martian landscape over time, giving spacesuit designers a better idea of how they degrade. When the first astronauts step on to Mars, they might have SHERLOC to thank for the suits that keep them safe.

About the Mission

Perseverance is a robotic scientist weighing about 2,260 pounds (1,025 kilograms). The rover’s astrobiology mission will search for signs of past microbial life. It will characterize the planet’s climate and geology, collect samples for future return to Earth, and pave the way for human exploration of the Red Planet. No matter what day Perseverance launches during its July 17-Aug. 11 launch period, it will land at Mars‘ Jezero Crater on Feb. 18, 2021.

The Mars 2020 Perseverance rover mission is part of a larger program that includes missions to the Moon as a way to prepare for human exploration of the Red Planet. Charged with returning astronauts to the Moon by 2024, NASA will establish a sustained human presence on and around the Moon by 2028 through the agency’s Artemis lunar exploration plans.

For more about Perseverance: