Space Sunday: super rockets, moon drones and emergency aborts

STP-2, June 2019, on FlickrA stunning timelapse view from the beaches of Florida as the Falcon Heavy STP-2 rocket arcs across the sky. Credit: Alex Brock

On Tuesday, June 25th, SpaceX launched their third Falcon Heavy Booster. Called STP-2, the primary aim of the mission was to help qualify the Falcon Heavy for US Department of Defence launches – but that didn’t stop it being the most ambitious mission for any SpaceX launch vehicle to date.

Carrying a total of 24 separate satellites into orbit, the vehicle had to deliver its payload to three distinct orbits around Earth, which in turn required the core stage of the rocket to fly fast enough to make its planned recovery at sea potentially problematic, while the upper stage had to make four individual engine burns – the most ever by a SpaceX launch vehicle.

Lift-off came at 02:30 ET, the rocket powering away from Kennedy Space Centre’s Pad 39-A. As a night-time launch, the flight provided a stunning view of what is called the “Falcon nebula”. This where, after the two Falcon 9 booster stages have separated from the core of the rocket, they flip themselves over while still increasing their altitude, and re-fire their engines to slow their forward momentum in order to start their descent back for a landing at Cape Canaveral Air Force Station. Together with the core booster’s motors still operating at full thrust, their exhausts can create a majestic pattern in the sky. In this case, given all of the three Falcon 9 boosters had been pushed to the limit, the vehicle was much higher in Earth’s rarefied atmosphere and this resulted in the boosters creating a remarkable pattern of colours against the night sky.

STP-2, June 2019, on FlickrThe “Falcon nebula”: the colourful plumes from the two Falcon 9 booster stages as they fire their motors in a “burn back” manoeuvre, with the core stage going at full throttle towards the bottom right. Credit: Alex Brock

Both of the Falcon 9 booster stages successfully completed their burn-back manoeuvres and made perfect landings at Cape Canaveral Air Force Station, just south of NASA’s Kennedy Space Centre. It had been hoped that the core stage would make it three-for-three by landing on one of the company’s two Autonomous Drone Landing Ships, parked some 1,200 km off the Florida coast. Unfortunately, such was the speed of the stage, it overshot the landing ship and crashed into the sea, smashing itself to pieces.

However, the loss of the core stage wasn’t the end of the good news for SpaceX. The upper stage continued on into orbit, successfully deploying its entire payload safely. And while it is said that re-naming a vessel can bring bad luck, that didn’t prove the case here, as the company’s high-speed chase vessel Go Ms Tree, which had previously been called Mr. Steven, finally and successfully caught one of the flight’s two payload fairings as they made a return to Earth.

Sea trials: the 62 m (205 ft) long Go Ms. Tree (formerly Mr. Steven), leased by SpaceX and converted to “catch” payload fairings in the huge net suspended over the stern deck, made its first successful catch with the STP-2 mission. Credit: Teslarati / SpaceX / Sea Tran

These where the two large “clamshells” that encase the payload during the flight through the denser part of Earth’s atmosphere. When the rocket’s upper stage is high enough, these are jettisoned and – in traditional flights – allowed to burn-up in the Earth’s atmosphere. However, at US $6 million a throw (a cost that has to be passed on to customers), SpaceX prefers to try to recover their payload fairings when they can. This means the fairing use their shape to ease their way into the denser atmosphere before deploying parachutes,  to land – and float – on the sea, but the company would prefer to keep them away from the corrosive influence of salt water.

Enter Go Ms Tree. Equipped with a large net over its stern deck, the ship is designed to move at speed under the flight path of returning fairings and snag them in the net. Six prior attempts to achieve this either failed or were abandoned, but on June 25th, the ship did successfully capture one of the returning fairings, although the second still had to make a splash down.

A Dragonfly for Titan

In December 2017, I wrote about a proposal to fly a nuclear-powered dual-quadcopter drone on Saturn’s moon, Titan. One June 27th, 2019, NASA confirmed the mission  – called Dragonfly – has now been officially selected for flight in what will be a tremendously ambitious long-duration mission, due to commence in 2026.

Titan is the only celestial body besides our planet known to have liquid rivers, lakes and seas on its surface, although they contain hydrocarbons like methane and ethane, not water. Nevertheless, they sit beneath a dense atmosphere which has commonalities with primordial atmosphere of Earth and which is rich in complex organic chemicals there such as tholins and polycyclic aromatic hydrocarbons, so these lakes and rivers could contain all the building blocks of life.

NASA Dragonfly: flying on Titan

Measuring 3 metres (10 ft) in length, Dragonfly is not s small vehicle. Designed by Johns Hopkins’ Applied Physics Laboratory (APL), it is intended to be a be a highly capable vehicle capable of carrying a full suite of science experiments while completing multiple flights on Titan. While the focus of the mission will be to try to determine how far prebiotic chemistry may have progressed there, the vehicle will carry a range of instruments as well, some of which will include:

  • DraMS (Dragonfly Mass Spectrometer), to identify chemical components, especially those relevant to biological processes.
  • DraGNS (Dragonfly Gamma-Ray and Neutron Spectrometer), to identify the composition of surface and air samples.
  • DraGMet (Dragonfly Geophysics and Meteorology Package), suite of meteorological sensors and a seismometer.
  • DragonCam (Dragonfly Camera Suite), a set of microscopic and panoramic cameras to image Titan’s terrain and landing sites that are scientifically interesting.

While the mission will launch in 2026, it will take almost eight years to get to Titan, arriving in 2034, when it will become the second vehicle to visit the moon’s surface after Europe’s Huygens lander, which travelled to Saturn and Titan as a part of the Cassini mission.

Dragonfly, June 2019, on FlickrThe planned landing location on Titan, marked by an X, and Dragonfly’s intended destination, the impact crater Selk, as imaged by the Visual Imaging and Mapping Spectrometer (VIMS) aboard the Cassini probe. Credit: NASA/JPL/UA

Once it has made a successful entry into Titan’s atmosphere, Dragonfly will fall clear of its protective aeroshell, start its rotor systems and make a soft landing on the area called the Shangri-La Dune Fields, which resemble dune fields in Namibia. Here it will carry out a series of flights of increasing length, until it is completing hops of up to 8 km (5 mi) as it makes way to the Selk impact crater. Along the way, it will take samples from the ground for analysis.

Titan is unlike any other place in the solar system, and Dragonfly is like no other mission. It’s remarkable to think of this rotorcraft flying miles and miles across the organic sand dunes of Saturn’s largest moon, exploring the processes that shape this extraordinary environment. Dragonfly will visit a world filled with a wide variety of organic compounds, which are the building blocks of life and could teach us about the origin of life itself.

– Thomas Zurbuchen, NASA’s associate administrator for Science

Selk crater is of interest because it is a geologically young impact crater 90 km (56 mi) in diameter. Infra-red measurements and other spectra gathered by Cassini show that the adjacent terrain exhibits a brightness possibly indicative of differences in thermal structure or composition, possibly caused by cryovolcanism that resulted from the impact. Such a mix of organic compounds and water ice pushed up for the subsurface ocean  in titan is a compelling target to assess just how far prebiotic chemistry may have progressed on Titan’s surface.

Studying Selk Crater and other locations on Titan should help scientists understand what conditions were like on the early Earth when life formed. We can’t go back in time on Earth and learn the lessons about the chemistry that eventually led to life, but we can go to Titan where we can pursue those questions.

– Curt Niebur, lead programme scientist for New Frontiers at NASA

Dragonfly is initially designed to operate for 2.7 years on Titan, but if the vehicle is successful, the mission could be extended much further. It is seen as a natural evolution of existing drone technology, using quad-copter flight systems that are well understood. The nature of Titan’s atmosphere means that flight testing can be  – indeed has been using developmental test vehicles – carried out on Earth. The plan is to supplement the flight systems  with algorithms for independent actions in real time, allowing the vehicle to operate entirely independently of commands from Earth – the sheer distance between Earth and Titan severely limiting communications.

Overall, the vehicle should have a flight range of around 175-180 km (109-112 mi) and wWhen airborne, it will be capable of speeds of up to 36 km/h and reach altitudes of up to 4 km. However, it will remain in the ground during the Titan nights – which last terrestrial days. Funded under NASA’s New Frontiers programme, development of the vehicle is cost-capped at US $650 million, and the total costs, including the launch vehicle and flight operations to Titan, is expected to be US $1 billion.

Orion Abort Flight Test

A critical component of NASA’s next crew-carrying spacecraft will be put to the test early next week.

On Tuesday, July 2nd, the agency plans to complete a further test of the Orion Multi-Purpose Crew Capsule’s launch-abort system, which is designed to get astronauts away from their rocket in the event of an emergency during launch.

The brief, uncrewed flight test will involve a 10,000 kg (22,000-lb) test version of Orion and a mini- rocket built by aerospace company Northrop Grumman. Lift-off will occur from Cape Canaveral Air Force Station in Florida during a 4-hour window that opens at 07:00 EDT (11:00 GMT).

During the 3-minute test, the spacecraft, with a fully functional launch abort system, will climb to an altitude of about 10  km (6 mi), reaching a speed of 1,600 km/h (1,000 mph). At that point, the system’s abort motor will fire, pulling Orion away from the booster.

The test is critical to moving Orion forward on the road to its first crewed flight, expected to take place in late 2020, and mark the start of NASA’s ability to send humans back to the Moon.

The launch and preview news conference will air on NASA TV and the agency’s website.

In Brief

2019 Total Eclipse

Also on July 2nd a solar eclipse will sweep across the South Pacific and a portion of South America. Skywatchers in parts of Chile and Argentina will be able to witness a total eclipse, in which the moon will block the Sun from view, with the exception of its wispy corona. In other parts of South America, a partial eclipse will be visit, in which it will look like a “bite” has been taken out of the Moon.

TimeAndDate.com will livestream the eclipse on YouTube beginning at 15:00. ET (19:00 GMT). Their webcast will feature live telescope views of the eclipse as well as the crowds of spectators watching it from South America, and experts will provide live commentary.

SpaceX targets 2021 for Super Heavy and Starship Launch

SpaceX has announced its massively ambitious Falcon Super Heavy booster and Starship combination is being targeted for a 2021 maiden cargo flight – and that three customers are in discussions with the company to make use of the vehicle.

Super Heavy and Starship are most widely known as being central to SpaceX CEO Elon Musk’s lunar and Mars aspirations, Starship being designed to transport cargo or up to 100 people (or a combination of people and cargo) to Mars. However, as a satellite launch system, the combination is designed to be capable of placing up to 20 tons into an geostationary orbit or geostationary transfer orbit.

SpaceX has indicated that it plans to launch its new Super Heavy and Starship combination with a payload in 2021. Credit: SpaceX via The Independent

Jonathan Hofeller, SpaceX’s vice president of commercial sales indicated that ahead of this first payload carrying launch, SpaceX plans to do several test flights with both vehicles. Those test flights — a number he did not quantify — are to demonstrate the launch system for customers and to assuage any concerns by insurers about the reliability of a new vehicle.

Given that thus fair, SpaceX has only flown a scale prototype of Starship less than a metre off the ground thus far (although they are fabricated the first Super Heavy core stage and indicated fabrication of the first full-size Starship is to be fabricated alongside of on-going tests of scale prototypes), the 2021 target date with test flights ahead of it – one of which must include certification – is ambitious.

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