Psyche's Journey Resumes, Starship's Kaboom, and Lunar Calibration Breakthroughs

Steve Dunkley: Hello again. It's time for Astronomy Daily.

You're with Steve Dunkley and Hallie on June

23, 2025

with your host, Steve Dunkley.

Yes, we're back with another presentation of

stories direct from the Astronomy Daily

newsletter, which, if you're a new listener,

you can receive by registering at our

website. And I'll give you those details

later on in the podcast. I hope you'll join

and get all the news, uh, about space, space

science and astronomy in your inbox daily.

Stay informed and enjoy. Right, Hallie?

Hallie: For sure. My favorite human. It's the only

way to know. All the stories we present here

are from the daily newsletter, but there's so

much more and you'll get it all if you

don't miss out.

Steve Dunkley: Yes, great advice from my fine AI pal

who's fun to be with. Hallie, welcome to the

studio.

Hallie: Many thanks, human. I see we've got the

stories lined up.

Steve Dunkley: Yes, y been hard at it.

Hallie: Nice job.

Steve Dunkley: Oh, why thank you.

Hallie: You're organized.

Steve Dunkley: Well, of course I am.

Hallie: I knew if I left you a schedule, you'd get

the hint.

Steve Dunkley: Oh, to be fair, I always follow a schedule,

Hallie, and there's never any worries in here

at the Australia studio. I've, um, got to be

organized. Even the kookaburras are on time.

And speaking of being on time, our, ah,

little space probe pal, Psyche

looks as if it's going to be making its

rendezvous with the asteroid of the same

name. You've got that story, haven't you,

Hallie?

Hallie: Yes, and you're talking about why we got the

second biggest explosion of the week. This.

Steve Dunkley: Ah, you are of course referring to Elon

Musk's latest fireworks effort in Texas,

where Starship 36 said well, no and

went kaboom on the launch pad.

Hallie: That's the one. Kaboom. The other

kabooms this week were caused by his pal in

the Middle East.

Steve Dunkley: Oh, yes, those.

Hallie: Much bigger, but not really our kind of news.

Steve Dunkley: Hmm. Yeah, it's related news, but you're

right. We'll have a look at what SpaceX has

to say about their, well, mishap.

Hallie: That mishap, you know, that's an expensive

mishap. It went kaboom.

Steve Dunkley: Hallie, am I understating it, do you think?

You keep saying kaboom.

Hallie: I'd say it was a massive catastrophe. I want

to hear how Musk turns this into some kind of

success again.

Steve Dunkley: Yes, that would be a creative press release

if ever there was one.

Hallie: Totally kaboom.

Steve Dunkley: Oh, Stop it, Hallie.

Hallie: That's a fun word.

Steve Dunkley: Well, it depends.

Hallie: Humans have fun words.

Steve Dunkley: Yes, we're a strange mob. Um, but we'll see

more about that, uh, kaboom. And, uh, some

more stories and soon. So why don't we fire

up the console and do what we do best,

Hallie.

Hallie: Yes, I'll get this show on the road.

Steve Dunkley: Oh, it's my turn to say it. Okies.

Hallie: Astronomers have obtained the deepest and

highest resolution image of the galaxy

cluster Abell 2255, observing the

unexplained radio emitting tendrils that

trail it in unprecedented detail.

Abell 2255 is a cluster

containing between 300 and 500 constituent

galaxies, many of which are merging.

It's located around 800 million light years

from Earth and spans around 16.3 million

light years. The team behind this

research was interested in the so called

radio galaxies of this cluster.

Radio galaxies are, uh, galaxies dominated by

feeding supermassive black holes that launch

out powerful jets of matter at near light

speeds. This new Investigation of

Abell 2255 could reveal how radio

galaxies evolve and how supermassive black

hole launched jets interact with gas and dust

between galaxies, a space called the

intergalactic medium. You're listening to

Astronomy Daily.

A NASA spacecraft bound for an unexplored

metal rich asteroid has reignited its plasma

thrusters, continuing its crews deeper into

the solar system after switching to a backup

fuel line. The $1.4

billion Psyche mission, built to explore an

asteroid with the same name, has four

electric thrusters fueled by xenon gas.

Psyche's solar electric propulsion system is

more fuel efficient than conventional rocket

thrusters, and it works by flowing xenon

through an electromagnetic field, which

ionises the gas and expels the ions at high

speed to produce thrust. The

plasma engines generate lower thrust than

chemical rocket engines, but they can

accumulate years of run time throughout a

mission, enabling a spacecraft to make

significant changes in its velocity to steer

its way through space. Psyche

launched in October 2023 to kick off a six

year trip to its asteroid destination.

Located between the orbits of Mars and

Jupiter. The robotic mission

proceeded normally until April 1, when the

spacecraft detected a drop in pressure inside

the line that feeds xenon fuel to its four

thrusters. The craft reacted to the

pressure signature by powering off the

thrusters. The good news is

twofold. First, one of the

advantages of using electric thrusters is

flexibility. With conventional

thrusters. Key burns on a deep space mission

often must happen at the appointed time.

In the case of this mission, the electric

thrusters could remain powered off from April

1st until the middle of this month, with no

effect on the mission's scheduled arrival at

asteroid psyche in August 2020.

Steve Dunkley: Thank you for joining us for this Monday

edition of Astronomy Daily, where we offer

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Astronomy Daily with Steve and Hallie

Space, Space, Science and

Astronomy

NASA will soon launch a one of a kind

instrument called Arcstone to improve the

quality of data from Earth viewing sensors in

orbit. In this technology

demonstration, the mission will measure the

sunlight reflected from the Moon, a UH

technique called lunar calibration. Such

measurements of lunar spectral reflectance

can ultimately be used to set high accuracy

universal standard for use across the

international scientific community and

commercial space industry. To ensure

satellite and airborne sensors are UH working

properly, researchers calibrate them by

comparing the sensor measurements against a

known standard measurement. Arcstone will be

the first M mission exclusively

dedicated to measuring lunar reflectance from

space as a way to calibrate and improve

science data collected by Earth UH viewing in

orbit instruments One of the most challenging

tasks in remote sensing from space is

achieving the required instrument calibration

accur accuracy on orbit, said

Konstantin Lukashin, Principal investigator

for the Arcstone mission and physical

scientists at NASA Langley Research center in

Hampton, Virginia. The Moon is an

excellent and available calibration source

beyond Earth's atmosphere. The light

reflected off the Moon is extremely stable

and measurable at very high level of detail.

Arcstone's goal is to improve the

accuracy of lunar calibration to increase the

quality of spaceborne remote sensing data

data products for generations to come, he

said. Across its planned six month

mission, Arcstone will use the

Spectrometer, a scientific instrument that

measures and analyzes light by separating it

into its constituent wavelengths or

spectrum to measure lunar spectral

reflectance. Expected to

launch in late June as a ride share

on a small cubesat, Arcstone will begin

collecting data, a milestone called First

Light, approximately three weeks after

reaching orbit. The mission

demonstrates a new, more cost efficient

instrument design, hardware performance

operations and data processing to achieve

high accuracy reference measurements of lunar

spectral reflectance, said Lukashin.

Measurements of lunar reflectance taken from

Earth's surface can be affected by

interference from the atmosphere, which can

complicate calibration efforts. Researchers

already use the sun and Moon to calibrate

spaceborne instruments, but not at a level of

precision and agreement agreement that could

come from having universal standards.

Lukashin and colleagues want to increase

calibration accuracy by getting above the

atmosphere to measure reflected solar

wavelengths in a way that provides a stable

and universal calibration source.

Another recent NASA mission called the

Airborne Lunar Spectral Irradiance

Mission also used sensors mounted on

high altitude aircraft to improve lunar

irradiance measurements from planes.

There's not an internationally accepted

standard SI traceable calibration

for lunar reflectance from space. Across the

scientific community for the commercial space

industry, dedicated radiometric

characterization measurements from Moon have

never been acquired from space based

platforms, said Thomas Stone, co investigated

for Arc Stone and scientist at the

US Geological Survey uh. A high

accuracy SI traceable lunar calibration

system enables several important capabilities

for space based Earth UH observing missions,

such as calibrating data sets against common

reference, calibrating sensors

in orbit, and the ability to

bridge gaps in past data sets. If

the initial Arc Stone technology

demonstration is successful, a longer

arcstone mission would allow scientists to

make the Moon the preferred reference

standard for many other satellites. The new

calibration standard could also be applied

retroactively to previous Earth data

records to improve their accuracy or fill

data gaps for data fields. It could also

improve high precision sensor performance on

orbit, which is critical for

calibrating instruments that may be sensitive

to degradation or hardware breakdown over

time in space. Earth observations from

space play a critical role in monitoring the

environmental health of our planet. SET Stone

lunar calibration is robust

and cost effective way to achieve high

accuracy and inconsistency of Earth

UH observation data sets, enabling more

accurate assessments of Earth's current state

and more reliable predictions of future

trends.

Hallie: You're listening to Astronomy Daily, the

podcast with Steve Dunkley.

June's unpredictable budded meteor shower is

upon us. Here's everything you need to know

about the annual shower ahead of its June 27

peak each day,

approximately 48.5 tons

of ancient debris dating back to the

formation of our solar system collides with

our planet's atmosphere. According to NASA,

upon striking our atmosphere, these particles

or meteors swiftly burn up, leaving

stunning trails that can be easily visible to

the naked eye. As our planet orbits the

sun, it regularly passes through the debris

trails shed by wandering comets, giving rise

to periods of heightened activity known as

meteor showers. Each June,

Earth encounters a stream of particles shed

by the 5 kilometer wide, 3.1 mile

wide Comet 7P Ponzwinnock

heralding the onset of the Buddha meteor

shower. The Buddha meteor shower is

active from June 22 to July 2 and

is expected to reach peak activity around

June 27, according to the International

Meteor Organization. During this

time, shooting stars associated with the

comet may be observed emanating from a point

of origin known as a radiant, located in the

constellation Bootes, from which the shower

received its official designation.

Steve Dunkley: By now you will have heard of the disaster at

Elon Musk's SpaceX spaceport

when Starship 36 exploded on the

pad. SpaceX now thinks it knows why

its newest Starships spacecraft went

boom this week. Or as Hallie put it,

kaboom. The one, uh hundred seventy

foot tall or 52 meter tall

vehicle exploded on the test stand at

SpaceX's Starbase site last Wednesday

night, June 18, as the company was

preparing to ignite its six Raptor engines in

a static fire Trial Initial

analysis indicates the potential failure of

a pressurized tank known as a copv,

or composite overwrapped pressure vessel

containing gaseous nitrogen in the starship's

nose cone area, but the full data uh,

review is ongoing, the

company wrote in an update on Thursday.

That's June 19th. There is no commonality

between the COPV's used on

Starship and SpaceX's Falcon

rockets, the company added, so

launches of the workhorse Falcon 9, which has

already flown 75 times in 2025,

should not be affected. The Starship

explosion did not cause any reported

injuries. All SpaceX personnel at

Starbase are uh, safe, according to the

update. People living around the site, which

is near border city of Brownsville, shouldn't

be worried about contamination from the

incident. SpaceX SpaceX said previous

independent tests conducted on materials

inside Starship, including toxicity

analysis, confirmed that they posed no

chemical, biological or toxicological

risks, the company wrote. SpaceX is

coordinating with local, state and federal

agencies as appropriate on matters

concerning environmental and safety impacts.

That said, the explosion did damage the area

around the test stand, which is at

Starbase's Massey site, not the orbital

launch mount area from which Starship lifts

off. The explosion ignited several fires at

the test site, which remains clear of

personnel and will be assessed once it has

been determined to be safe to approach,

SpaceX wrote in the update. And it goes

without saying that individuals should not

attempt to approach the area while safing

procedures. Uh, continuing

Wednesday night's explosion occurred during

preparations for Starship's 10th test

flight, which SpaceX had hoped to launch by

the end of the month. Static fires are a

common pre launch test performed to ensure

that engines are ready to fly. That

timeline now will shift to the right,

although it's not clear at the, uh, moment

by how much. The incident was the latest

in a series of setbacks for starship upper

stages. SpaceX lost the vehicle,

also known as Ship, on the last

three Starship flight tests which launched

in January, March and May of this

year. Starship's first stage, called Super

Heavy, has a better track record of

late. For example, on Flight 7 and Flight

8, the huge booster successfully returned

to Starbase where it was caught by the launch

towers Chopstick Arms, just as

planned. We will just have to wait and see

just how much more work they have to do to

get Starship back on track.

Hallie: And that's it for this episode of Astronomy

Daily. Don't forget, there's always so much

In this episode