Experiment devoted to neutron star research installed on space station

Artist’s concept of a pulsar (blue-white disk in center) pulling in matter from a nearby star (red disk at upper right). The stellar material forms a disk around the pulsar (multicolored ring) before falling on to the surface at the magnetic poles. The pulsar’s intense magnetic field is represented by faint blue outlines surrounding the pulsar. Credit: NASA

A NASA instrument built to help astronomers learn about the structure and behavior of neutron stars, super-dense stellar skeletons left behind by massive explosions, has been mounted to an observation post outside the International Space Station after delivery aboard a SpaceX supply ship earlier this month.

Since its arrival inside the trunk of SpaceX’s Dragon cargo capsule, the X-ray astronomy experiment has been transferred from the spacecraft’s unpressurized carrier to a platform on the space-facing side of the space station’s starboard truss backbone, powered up and checked to ensure it can point at stellar targets as the research outpost orbits around Earth.

The Neutron Star Interior Composition Explorer, or NICER, is now going through alignment checks and test scans, allowing scientists to fine-tune the instrument. The calibrations should be complete next month, and NICER’s ground team has penciled in July 13 as the first day of the instrument’s 18-month science mission.

NICER’s developers at NASA’s Goddard Space Flight Center crammed 56 individual X-ray mirrors inside the instrument’s shell, with matching silicon detectors that will register individual photons of X-ray light, measuring their energies and times of arrival.

NASA says NICER is the first mission dedicated to neutron star research. Astronomers discovered neutron stars in 1967, decades after scientists first predicted their existence.

Neutron stars are left behind after lower-mass stars exploded in violent supernovas at the ends of their lives. The material from the star ends up crammed into an object the size of a city, and astronomers say one of the densest stable forms of matter in the universe resides in the deep interiors of neutron stars.

The NICER instrument. Credit: NASA

Scientists compare the density of a neutron star to packing the mass Mount Everest into a sugar cube. One teaspoon of neutron star matter would weight a billion tons on Earth, according to NASA.

NICER flew to the space station inside the rear trunk of a SpaceX Dragon supply ship, which launched June 3 from NASA’s Kennedy Space Center in Florida and berthed with the orbiting outpost June 5.

The station’s Canadian-built robotic arm extracted the NICER experiment from the Dragon spacecraft June 11, and the instrument rode to its mounting location on an external platform — EXPRESS Logistics Carrier-2 — on a mobile rail car down the station’s truss.

Mission controllers in Houston commanded and monitored the multi-day transfer from the ground, with the help of the station’s two-armed Dextre robot.

The space station’s robotic arm installed NICER on its mounting plate June 13, and controllers powered up the instrument’s electronics the next day, verifying all systems were OK. Range of motion tests were completed Friday after engineers needed extra time to release troublesome launch restraint bolt

NASA experiment dedicated to neutron star research installed on space station after delivery by SpaceX this month. https://t.co/hUe7VEhd5p pic.twitter.com/FYvbsm8xP5

— Spaceflight Now (@SpaceflightNow) 20 de junio de 2017

NICER rode to the space station with two other experiments in Dragon’s trunk.

One of the payloads, sponsored by the Air Force Research Laboratory, will test a new solar array design could be used on future commercial satellites, making the power generators 20 percent lighter and able to fit into a launch package four times smaller than conventional fold-out solar panels.

A commercial Earth-imaging platform developed by Teledyne Brown was also stowed in Dragon’s trunk. The Multiple User System for Earth Sensing, or MUSES, can host high-definition and hyperspectral cameras for Earth-viewing.

The MUSES payload was robotically moved to its new home on the space station before NICER, and the solar array testbed was unfurled for seven days of testing this week.

The installation of NICER clears the way for nearly a month of calibrations before it can start regular science observations.

“Neutron stars are fantastical stars that are extraordinary in many ways,” said Zaven Arzoumanian, NICER’s deputy principal investigator and science lead at Goddard. “They are the densest objects in the universe, they are the fastest-spinning objects known, they are the most strongly magnetic objects known.”

The NICER science team wants to know the structure and composition of neutron stars, which are so extreme that normal atoms are pulverized, freeing subatomic particles like neutrons, protons and electrons.

“As soon as you go below the surface of a neutron star, the pressures and densities rise extremely rapidly, and soon you’re in an environment that you can’t produce in any lab on Earth,” said Slavko Bogdanov, a research scientist at Columbia University who leads the NICER light curve modeling group.

A view of the space station’s Canadian-Built robotic arm removing NICER instrument from its berth inside SpaceX’s Dragon capsule last week. Credit: NASA

Unlike black holes, which develop from explosions of stars more than 20 times the mass of the sun, neutron stars can be directly observed.

A partnership between NASA, the Massachusetts Institute of Technology and the Naval Research Laboratory, NICER should give scientists their first measurements of the size of a neutron star.

“They emit light all across the spectrum, from radio waves to visible light up to X-rays and gamma rays, primarily in narrow beams from their magnetic poles,” Arzoumanian said. “Just like the Earth, the magnetic poles on a neutron star are not necessarily aligned with the spin of the star, so you can get narrow beams that sweep as the star spins, just like a lighthouse.

“And if we happen to be in the path of the sweep we see a flash everytime one of these beams go by and the stars from a distance appear to be pulsing, so they’re called pulsars,” Arzoumanian said.

Scientists will also demonstrate the potential of using the timing of pulses from neutron stars for deep space navigation.

“We’re going to look at a subset of pulsars in the sky called millisecond pulsars,” said Keith Gendreau, NICER’s principal investigator at Goddard. “In some of these millisecond pulsars, the pulses that we see are so regular that they remind us of atomic clocks.”

Atomic clocks are the basis of the Global Positioning System satellites, according to Gendreau.

NASA calls the navigation demonstration the Station Explorer for X-ray Timing and Navigation Technology, or SEXTANT.

Jason Mitchell, SEXTANT’s project manager at Goddard, said his team aims to use predictable pulsar signals to locate the space station with a precision of 6 miles, or 10 kilometers, without the aid of GPS satellites or on-board navigation solutions.

“That’s a small step compared to GPS, but it’s a giant step for using only pulsar measurements, and that will help us get into deep space,” Mitchell said.

“Our goal is to turn the G in GPS into galactic, and make it a Galactic Positioning System,” he said.

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Chinese broadcasting satellite ends up in wrong orbit after rocket failure

File photo of a previous Long March 3B launch. Credit: Xinhua

Ground controllers could try to salvage a Chinese television broadcasting satellite deployed in a lower-than-planned orbit Sunday by a Long March 3B rocket.

A brief statement from the China Aerospace Science and Technology Corp., a state-run contractor for China’s space program, confirmed an anomaly in the Long March 3B rocket’s third stage left the Chinasat 9A communications satellite in the wrong orbit following a liftoff from the Xichang space center.

An investigation into the cause of the launch failure is underway, CASC said.

The contractor said the Chinasat 9A satellite separated from the Long March 3B’s third stage after the anomaly and deployed its electricity-generating solar panels and antennas. The spacecraft is apparently healthy and in contact with engineers on the ground, who are taking “relevant efforts” to control the satellite, according to CASC.

Officials did not elaborate on what went wrong on the Long March 3B’s third stage, which is powered by a dual-nozzle YF-75 engine that burns a mixture of liquid hydrogen and liquid oxygen propellants.

Sunday’s launch mishap was the first time one of China’s Long March 3-series rockets has failed to deliver a payload into its intended orbit since August 2009. Variants of the Long March 3 rocket, which include configurations with and without strap-on boosters, logged 49 straight successful launches in the last seven-and-a-half years.

China’s other Long March rockets, which use the same engine technology as the Long March 3-series, have suffered failures in recent years. A Chinese Earth observation satellite was destroyed during the botched launch of a Long March 4C booster Sept. 1, and a Long March 2D placed a pair of commercial Earth-imaging spacecraft into a lower-than-intended orbit in December, but those satellites recovered from the rocket mishap.

A diagram of China’s Long March 3 family of rockets. The Long March 3B, center, features four strap-on boosters. Credit: China Great Wall Industry Corp.

U.S. military tracking data indicated Chinasat 9A is orbiting around Earth at altitudes ranging between 120 miles (193 kilometers) and approximately 10,165 miles (16,360 kilometers), significantly lower than intended.

The rocket’s upper stage aimed to release Chinasat 9A in an egg-shaped elliptical orbit with an apogee, or high point, around 35,800 kilometers (22,300 miles) above Earth.

Chinasat 9A carried its own fuel to circularize its orbit more than 22,000 miles over the equator following its deployment from the Long March 3B. If the satellite is able to overcome the altitude deficit after Sunday’s launch, it will have to consume more of its on-board propellant supply than expected, likely shortening its useful life.

In addition to the orbit-raising maneuvers needed to reach its final operating position, Chinasat 9A must also reshape its orbit, which is currently tilted 25.7 degrees to the equator, into one that always hovers over the equator.

The 184-foot-tall (56-meter) Long March 3B rocket lifted off with Chinasat 9A at 1611 GMT (12:11 p.m. EDT) Sunday from the Xichang launch base in southwestern China’s Sichuan province.

The liquid-fueled launcher, comprised of a three-stage core and four strap-on boosters, turned east from Xichang after blasting off at 12:11 a.m. Monday, Beijing time.

Chinese media did not release any photos of the launch, but an amateur video from Xichang shared on Twitter shows the rocket taking off just after midnight.

【ZX-9A】2017年6月19日00:12，长征三号乙运载火箭发射中星9A直播卫星 pic.twitter.com/eUpgbBYehg

— ChinaSpaceflight (@cnspaceflight) 18 de junio de 2017

The early portion of the mission went according to plan, and the Long March shed its four boosters and first stage a few minutes after liftoff. A second stage firing also apparently performed well, and the third stage took over nearly six minutes into the flight for the first of two burns needed to place Chinasat 9A into a geostationary transfer orbit.

The third stage’s first engine firing was expected to cut off around 10 minutes after liftoff to propel Chinasat 9A into a preliminary low-altitude orbit, and a second burn a few minutes later was supposed to send the spacecraft toward its high-altitude target.

Chinasat 9A, with a launch mass estimated in excess of 11,000 pounds (5 metric tons), was scheduled to separate from the Long March 3B’s third stage less than a half-hour after liftoff.

Based on the DFH-4 satellite design built by the China Academy of Space Technology, Chinasat 9A is China’s first domestically-made communications satellite for direct-to-home television broadcasting, according to China Satcom, the craft’s owner and operator.

Chinasat 9A was supposed to enter service later this year in geostationary orbit over the equator at 101.4 degree east longitude, where its orbital velocity would match the speed of Earth’s rotation, making the satellite remain fixed over the same geographic coverage area.

The satellite’s 24 Ku-band transponders are designed to provide television broadcasts and other media services to China Satcom customers in China, Hong Kong, Macau and Taiwan, the company said.

Proton-M returns to flight with launch of EchoStar

Launch of the Proton-M / EchoStar 21 mission rocket. Photo Credit: Roscosmos

After a delay of nearly one year, International Launch Services (ILS) launched the EchoStar 21 communications satellite atop a Proton-M rocket from Site 81/24 at Baikonur Cosmodrome in Kazakhstan. Liftoff took place at 11:45 p.m. EDT on June 7 (03:45 GMT on June 8), 2017.

The mission is tasked with delivering the EchoStar 21 satellite into a geostationary transfer orbit (GTO). The flight will last slightly more than nine hours, counting from launch until spacecraft separation.

EchoStar 21 has come a long way to get to this point. The project dates back to 2005 when TerreStar Networks, Inc. finished final design reviews for the TerreStar-1 satellite that was launched into space in 2009. The TerraStar-2 spacecraft was ordered in 2006 and was renamed to EchoStar 21 in 2012 when Englewood, Colorado-based company EchoStar acquired all of TerreStar Network’s assets.

PROBLEMS AND DELAYS

An agreement to launch the EchoStar 21 satellite was signed with ILS in May 2013, initially targeting the end of 2015 for liftoff. However, the mission has faced several delays. First, it was postponed to June 2016; however, in May of that year, it was rescheduled to August 29, 2016.

Later, on July 28, it was decided the launch needed to be postponed to October 2016 due to the prolonged investigation into the problem with the Proton-M’s second stage that occurred after the June 9, 2016, liftoff. Then it was rescheduled for December 2016 before being delayed into 2017.

Then in early 2017, problems were discovered with the launch vehicle’s engines, prompting further investigation.

Finally, in late May 2017, a firm launch date of June 7 (June 8 local time) was set. By this time, Proton had experienced its longest delay in its history: about 364 days. The record before this was 247 days in 1966 into 1967

The Proton-M / EchoStar 21 mission rocket on the launch pad. Photo Credit: Roscosmos

PROTON-M

The 190-foot (58-meter) tall Proton-M booster measures some 13.5 feet (4.1 meters) in diameter along its second and third stages. Its first stage has a diameter of 24.3 feet (7.4 meters). The total overall height of the rocket’s three stages is about 138.8 feet (42.3 meters).

The first stage consists of a central tank containing the oxidizer surrounded by six outboard fuel tanks. Each fuel tank also carries one of the six RD‑275M engines that provide power for the first phase of flight. The cylindrical second stage is powered by three RD-0210 engines along with a single RD‑0211 engine.

A single RD-0213 engine and a four-nozzle vernier engine powers the third stage. Guidance, navigation, and control of the Proton-M during operation of the first three stages is carried out by a triple-redundant closed-loop digital avionics system mounted in the third stage.

Topping off the rocket is the Breeze-M upper stage. It is powered by a pump-fed gimbaled main engine. This stage consists of a central core and an auxiliary propellant tank (APT) that is jettisoned in flight after the depletion of its fuel. The stage’s control system includes an onboard computer, a three-axis gyro stabilized platform, and a navigation system

THE MISSION

The countdown that led the Proton-M rocket to the ignition of its engines commenced about 11.5 hours ahead of liftoff. The launch vehicle and its systems were activated about six hours before the launch, enabling fueling operations. The campaign entered its final phase approximately 45 minutes before ignition when final checkouts of all systems were performed and the launch abort system armed.

The last five minutes of the pre-launch phase was the most crucial as the automated countdown sequence began, switching the launch vehicle to internal power. About two minutes before liftoff, propellant tank pressurization took place and engineers had their last opportunity to conduct health checks of the rocket’s Breeze-M upper stage. With all systems declared “go”, the Proton-M ignited its six RD-275M boosters to begin climbing toward space.

Photo Credit: Roscosmos

Maximum dynamic pressure, or max Q, occurred about 62 seconds after liftoff. It was at this point the vehicle endured its maximum stresses.

Stage one and two separated less than a minute later at two minutes after liftoff. The second stage continued burning for about 3.5 minutes before it too cut off and separated.

At this point, the third stage had taken control. It fired at 5 minutes, 26 seconds after liftoff. Nineteen seconds later, the payload fairing jettisoned, revealing the Breeze-M upper stage and the EchoStar 21 satellite.

At 9 minutes, 41 seconds after leaving the launch pad in Baikonur, the third stage cut off and separated from the Breeze-M. About 1.5 minutes after that, it too ignited to finish the climb to orbit.

Fifteen minutes, 32 seconds after liftoff, Breeze-M with EchoStar 21 was in a parking orbit. The first of five burns the upper stage needed to do was complete.

After coasting for 54 minutes, the Breeze-M ignited again and burned for about 18 minutes. This intermediate orbit had a low point of 168 miles (270 kilometers) and a high point of 3,107 miles (5,000 kilometers).

The Breeze-M and EchoStar 21 then coasted again for about two hours before the third upper stage ignition occurred. This burn started 3 hours, 37 minutes, and 36 seconds after liftoff; it continued for just under nine minutes. At its conclusion, the APT jettisoned.

About 1.5 minutes later, the fourth burn started. This seven-minute burn concluded at a mission elapsed time of 3 hours, 47 minutes, 53 seconds.

Coasting again, the Breeze-M upper stage had a five-hour break before its final burn.

That burn occurred 8 hours, 52 minutes, 58 seconds after leaving Baikonur. The primary objective of this 4.5-minute burn was to change the inclination of the vehicle and satellite from 51.5 degrees relative to the equator to just 30.5 degrees. The low point of its orbit was now 1,429 miles (2,300 kilometers) and the high point was 22,236 miles (35,786 kilometers).

At 9 hours, 13 minutes mission elapsed time, the EchoStar 21 satellite separated from the Breeze-M.

The 6.8-metric ton EchoStar 21 is based on SSL’s 1300 spacecraft platform and features two deployable solar arrays and a large un furlable reflector.

Once the spacecraft’s onboard propulsion to circularize its orbit, EchoStar 21 will be in a geostationary orbit at the 10.25 degrees East orbital slot where it will provide its services for 15 years.

EchoStar describes the newest addition to its in-orbit fleet as a state-of-the-art S-band satellite designed to provide mobile connectivity throughout Europe.

This was the first ILS Proton launch in 2017 and the 94th ILS Proton launch overall. Additionally, six EchoStar satellites have now been launched by the company atop Proton rockets.

In total, 413 Proton rockets have launched since 1965. Since 2001, 90 Proton-M variants have launched using the Breeze-M upper stage.

This was the third launch from Baikonur Cosmodrome in 2017. The next mission from that spaceport will be the Progress MS-06 cargo ship bound for the International Space Station. It will take to the skies at 5:20 a.m. EDT (09:20 GMT) on June 14, 2017.

The Proton-M / EchoStar 21 mission rocket on the launch pad. Photo Credit: Roscosmos,

Photo Credit: Roscosmos,

Photo Credit: Roscosmos

Photo Credit: Roscosmos

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