Austin: No Plans to Shoot Down Errant Chinese Rocket Stage – UPDATE 3

Austin: No Plans to Shoot Down Errant Chinese Rocket Stage – UPDATE 3

As global concerns rise about where China’s Long March-5B rocket stage might land, Secretary of Defense Lloyd Austin said today DOD has no plans to shoot it down. Predicting when and where it will impact Earth is fraught with difficulties, but at the moment it is in the May 8-9 time frame almost anywhere on the planet. Still, the chances of it hitting a particular individual are very small. FINAL UPDATE, U.S. Space Command reports that the LM-5B rocket stage reentered over the Arabian Peninsula at approximately 10:15 pm EDT May 8. “It is unknown if the debris impacted land or water.” Separately, NASA Administrator Bill Nelson criticized China for “failing to meet responsible standards regarding their space debris.” Reports are that debris fell near the Maldives. China’s Xinhua reported a slightly different time (May 9 10:24 am Beijing Time, or May 8 10:24 pm EDT) and said the “vast majority” of the rocket disintegrated and the rest of the debris fell in  the sea in an area centered at 2.65 degrees North, 72.47 degrees East.

The rocket launched the Tianhe core module for China’s new space station on April 28, 2021 Eastern Daylight Time (April 29 in China) from the Wenchang Satellite Launch Center on Hainan Island.

Launch of Tianhe space station module on Long March-5B from Wenchang Satellite Launch Center, Hainan Island, China, April 28 EDT/April 29 China Standard Time. Credit: Xinhua tweet @XHsciTech

This version of the Long March-5, the Long March-5B (LM-5B), has a single core stage that goes into orbit along with the payload. After they separate, it reenters Earth’s atmosphere. (The LM-5B also has four strap-on rockets that detach before reaching orbit.)

The Long March-5 family is new and this was only the second launch of the 5B.

Reentering rocket stages are quite common, but usually they are smaller second stages and most of the mass burns up during the fiery reentry through the Earth’s atmosphere. Many launch vehicles include a capability to intentionally deorbit those stages so they make a controlled reentry away from populated areas, usually the Pacific Ocean. Sometimes the deorbit systems do not work, as happened recently with a SpaceX launch, but what survives all the way to the ground is less than with a massive object like the LM-5B.

Long March is Chang Zheng in Chinese and the rocket is also referred to as CZ-5B.

U.S. Space Command’s 18th Space Control Squadron (18 SPCS) tracks everything orbiting Earth and produces “Two Line Elements” (TLEs) with designators and orbital characterizes of every object. This is object 48275 with the international designator 2021-035B and satellite name CZ-5B R/B (for rocket body).

TLEs for unclassified objects are available free to the public on allowing experts around the world to make their own reentry predictions in addition to those provided by 18 SPCS itself.

The Aerospace Corporation, a federally funded research and development center that supports the U.S. government’s national security space sector, is highly respected for its reentry analyses.

At the moment, it is predicting reentry on May 9 at 04:43 UTC ± 16 hours or May 8 at 23:43 EDT ± 16 hours.

That’s a 32 hour time window covering most of this weekend EDT. Reentry is affected by many factors including the shape, size and mass of the object as well as atmospheric effects from the Sun. The error bars around a predicted reentry time can be quite large in the beginning, but narrow as reentry nears.  Aerospace is posting updates to its calculations regularly.

LM-5B can come down anywhere on the globe under its flight path between 41.5 degrees North and 41.5 degrees South latitude.

The Aerospace Corporation’s ground track for Object 2021-035B, Long March-5B rocket body. The areas marked in blue and yellow are possible locations where reentry could occur. For more information and a full legend, visit Aerospace’s website.

Although it overflies heavily populated regions, it is important to bear in mind that 70 percent of the globe is water and Aerospace’s Marlon Sorge points out that only about 20-40 percent of an object’s mass will survive reentry.

Despite the size (98 feet long, 21.5 feet in diameter, 21.5 MT), the chances of an individual being hit are very, very small.  Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics, tweeted some perspective.

However, the flight path does cover a fair amount of the United States, including major cities like New York, Miami, Los Angeles, and Washington, D.C.

Asked if DOD has any plans to try and shoot down the rocket stage, Austin told reporters today the answer is no.

At this point we don’t have a plan to shoot the rocket down. We’re hopeful it will land in a place where it won’t harm anyone. Hopefully in the ocean or someplace like that. I think this speaks to the fact that for those of us who operate in the space domain that there should be a requirement to operate in a safe and thoughtful mode and make sure that we take those kinds of things into consideration as we plan and conduct operations. — Secretary of Defense Lloyd Austin

At yesterday’s White House press briefing, Press Secretary Jen Psaki also was asked about a U.S. response and responded more generally about space debris.

The United States is committed to addressing the risks of growing congestion due to space debris and growing activity in space.  And we want to work with the international community to promote leadership and responsible space behaviors.  It’s in the shared interests of all nations to act responsibly in space to ensure the safety, stability, security, and long-term sustainability of outer space activities. — White House Press Secretary Jen Psaki

Andrew Jones, who closely follows the Chinese space program, can only speculate as to why China did not include a deorbit system. Via email, he suggested that perhaps “the risk of such a reentry was considered more favourable than reducing safety margins for putting” space station modules into orbit. “A senior Chinese official involved in the Long March 5B project stated after the successful launch last week that 47 improvement measures had been made since the first launch, but core stage deorbiting capabilities were not mentioned.”

He added that a “Chinese Foreign Ministry spokesperson was today asked about the issue twice, but the answer essentially failed to even acknowledge the issue at hand.”

Austin also was asked if the United States has the capability to shoot it down. He replied “we have the capability to do a lot of things, but we don’t have a plan to shoot it down as we speak.”

It is not an easy task to destroy a space object without creating a cloud of space debris that can pollute space for decades.  In 2008, DOD destroyed one of its own satellites, USA-193, that failed soon after launch and risked spreading toxic fuel over populated areas if it made an uncontrolled reentry. Called Operation Burnt Frost, Nick Johnson, NASA’s top orbital debris expert at the time, recently wrote a first hand account of the planning required to pull that off successfully even when every detail of the satellite’s design was known. Johnson passed away last month.

In addition to the concern about where this particular rocket stage will end up, a broader worry is that there are more of them to come. This is only the second launch of the LM-5B.  The core stage of the first launch in July 2020 also made an uncontrolled reentry, prompting a rebuke from then-NASA Administrator Jim Bridenstine.

China’s other three launch sites are inland and the government has demonstrated a cavalier attitude about where rocket stages land on its own territory, a tale told in photos tweeted by Jones and others.

Chinese officials are somewhat sensitive to international scorn, however. After China’s first space station, Tiangong-1, made an uncontrolled reentry in 2018 amid global condemnation, it kept enough fuel aboard its second, Tiangong-2, to permit a controlled reentry in 2019.

Those were very small 8.5 Metric Ton (MT) space stations. This new China Space Station is multi-modular with two more modules yet to be launched. All need the LM-5B’s lift capacity and this is just the beginning of China’s space ambitions.

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