homehome Home chatchat Notifications


What China's latest X-ray positioning satellite means for deep-space exploration

Made in China might become a stamp for innovation, not replication.

Tibi Puiu
November 30, 2016 @ 1:20 pm

share Share

A rendering of China's XPNAV-1 satellite (CAST).

A rendering of China’s XPNAV-1 satellite (CAST).

On November 10, aboard a Long March 11 rocket, China launched a suite of satellites into space. Among them was the innovative X-ray Pulsar Navigation 1 (XPNAV 1) satellite which is equipped with a world’s first instrument that offers X-ray-based navigation. Unlike classical satellites and spacecraft that rely on GPS-like features, the XPNAV 1 uses X-ray sources from space like those emitted by pulsars to triangulate its position. In other words, this tiny satellite is paving the way for a new class of spacecraft that will not only breach the final frontier but also find its way around it.

To send spacecraft to Jupiter or land them on a comet, scientists require deep space navigation with incredible precision, as otherwise, the spacecraft would just crash in the first junk it encounters in space. To navigate these spacecraft, we generally set our own planet as a reference point. We know Earth’s  orbital parameters and inherent motions very well, so it’s just a matter of measuring the craft’s distance from Earth, the component of its velocity that is directly toward or away from Earth, and its position in Earth’s sky. These parameters are then converted to a sun-centric model.

This workflow has worked very well so far, but what happens if you want to exit the solar system? Because the craft is now many billions of miles away from Earth, it’s much harder to track and navigation can become increasingly skewed. As the craft gets farther and farther away from Earth, it will eventually travel in the dark.

The XPNAV 1 bypasses these limitations by reading deep space X-ray pulses given off by pulsars —  highly magnetized, rotating neutron stars. The pulsar rapidly rotates around its own axis producing X-ray pulses at short intervals. The way your phone uses GPS to find your location is it sends electromagnetic pulses to multiple satellites then, based on the response time, it triangulates the position. Similarly, XPNAV 1 reads various X-ray pulses of predictable nature and location to locate itself with an accuracy of 5 kilometers (3.1 miles). The error sounds like a lot (it really is too close for comfort) but scientists believe they can get more accurate positioning by finding pulsars with more consistent pulses.

NASA has it’s own X-ray pulsar navigation satellite too, the Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) mission. However, the satellite will launch in 2017 and China seems to have undercut NASA by a couple of months.

XPNAV 1 is innovative, a word you won’t normally use to describe something made in China, but that may soon change. China’s President Xi Jinping is betting on space big time and wants to triple government spending on scientific research. His hope is a new wave of innovations will come out of China, one that will inspire future generations and startups.

“China has been relying on the knowledge discovered by others,” said in a statement Wu Ji, director-general of the National Space Science Center, who’s spearheading the effort to lobby for more space missions with possible economic spinoffs. “If China wants to rejuvenate the economy, it needs to put more resources into developing groundbreaking technologies.”

As part of China’s ongoing five-year-plan, the nation hopes to produce 70 percent of key technology components—such as semiconductors and software— domestically by 2025.

Other major milestones for Chinese space exploration which happen this year include the launch of the Tiangong-2 space lab, the world’s first quantum science satellite and the debut of the new generation Long March 7 rocket.

share Share

Frozen Wonder: Ceres May Have Cooked Up the Right Recipe for Life Billions of Years Ago

If this dwarf planet supported life, it means there were many Earths in our solar system.

Are Cyborg Jellyfish the Next Step of Deep Ocean Exploration?

We still know very little about our oceans. Can jellyfish change that?

Can AI help us reduce hiring bias? It's possible, but it needs healthy human values around it

AI may promise fairer hiring, but new research shows it only reduces bias when paired with the right human judgment and diversity safeguards.

Hidden for over a century, a preserved Tasmanian Tiger head "found in a bucket" may bring the lost species back from extinction

Researchers recover vital RNA from Tasmanian tiger, pushing de-extinction closer to reality.

Island Nation Tuvalu Set to Become the First Country Lost to Climate Change. More Than 80% of the Population Apply to Relocate to Australia Under World's First 'Climate Visa'

Tuvalu will likely become the first nation to vanish because of climate change.

Archaeologists Discover 6,000 Year Old "Victory Pits" That Featured Mass Graves, Severed Limbs, and Torture

Ancient times weren't peaceful by any means.

Space Solar Panels Could Cut Europe’s Reliance on Land-Based Renewables by 80 Percent

A new study shows space solar panels could slash Europe’s energy costs by 2050.

A 5,000-Year-Old Cow Tooth Just Changed What We Know About Stonehenge

An ancient tooth reshapes what we know about the monument’s beginnings.

Astronomers See Inside The Core of a Dying Star For the First Time, Confirm How Heavy Atoms Are Made

An ‘extremely stripped supernova’ confirms the existence of a key feature of physicists’ models of how stars produce the elements that make up the Universe.

Rejoice! Walmart's Radioactive Shrimp Are Only a Little Radioactive

You could have a little radioactive shrimp as a treat. (Don't eat any more!)