I’ve been busy with the conference, compounded by the fact that I brought the wrong mouse with me for the laptop, so light posting. But it’s worth noting the anniversary of the loss of Challenger. Which is also (as always) my birthday.
I’ve been busy with the conference, compounded by the fact that I brought the wrong mouse with me for the laptop, so light posting. But it’s worth noting the anniversary of the loss of Challenger. Which is also (as always) my birthday.
Happy Birthday, Rand!
Hopefully after 40 years NASA has actually done their homework and not just PowerPointed away the flaws in Artemis.
I think Feynman would flip his lid if he was still alive. Here NASA goes again, normalizing anomalies. Hey, it didn’t blow up last time so it’s probably fine, right?
Right? Right? C’mon Ed, the week before a launch is a hell of a time to establish launch criteria!
Happy birthday, may you get to do all the things you want to today.
Happy birthday. Eventually I hope to be able to attend conferences again. I really miss Space Access.
Bon anniversaire.
https://x.com/Amazonleo/status/2016620278986506438
Happy Birthday, Rand. Many returns.
Hoping you have the happiest of birthdays.
Happy Belated Birthday Rand.
Let’s pray that Artemis II does not reprise…
I still don’t plan to watch it. I’ll follow it here on this blog.
It’s been on my mind a lot this week. Esp. with record cold in Florida. It is just me or is nobody else paying attention? Well I know Robert Zimmerman is. And probably Charles Camarda.
Speaking of Robert Z: Normalizing the anomaly, to stay on schedule…
Is it Science or Faith-Based simulation?
Happy belated Birthday!
Somewhat off topic but interesting:
‘The director of the National Reconnaissance Office (NRO) recently declassified the existence of JUMPSEAT: the United States’ first-generation, highly elliptical orbit (HEO) signals-collection satellite.’
https://www.nro.gov/news-media-featured-stories/news-media-archive/News-Article/Article/4392223/declassifying-jumpseat-an-american-pioneer-in-space/
In furtherance of a good thread hijack… This prompted a ridiculous yet educational query to Grok from me. Always willing to learn…
“Is it possible to fly a highly elliptical (Molniya) orbit around the Earth’s Equator rather than the Poles?”
No, a classic Molniya orbit cannot realistically be flown around Earth’s equator (i.e., with 0° or very low inclination). The defining characteristics and advantages of a Molniya-type orbit are incompatible with an equatorial plane.
A Molniya orbit is a specific kind of highly elliptical orbit (HEO) with these key properties:
Orbital period ≈ 12 hours (half a sidereal day)
High eccentricity (typically ~0.7–0.74), so perigee ~500–2,000 km and apogee ~40,000 km
Inclination fixed at ~63.4° (the critical inclination where J₂ oblateness perturbations cause zero secular change in the argument of perigee — a “frozen orbit”)
Argument of perigee ~270° (apogee placed over the northern hemisphere)
This combination allows the satellite to spend most of its time (≈8–10 hours per 12-hour orbit) dwelling near apogee high over northern high-latitude regions (e.g., Russia, northern Europe, Canada), while zipping quickly through perigee over the southern hemisphere. It was invented precisely to provide quasi-stationary coverage of high latitudes from launches at high-latitude sites like Baikonur, where reaching equatorial (0°) geostationary orbit is very expensive in Δv.
Why an Equatorial Version Doesn’t Work as a “Molniya Orbit”
Inclination must be ~63.4° to freeze the argument of perigee. At 0° inclination, the argument of perigee would precess rapidly due to Earth’s oblateness (J₂ term). The apogee location would drift around the equator over weeks/months, destroying the stable “dwell” over any particular longitude.
An equatorial highly elliptical orbit (0° inclination, high eccentricity, ~12-hour period) is technically possible to achieve, but:
It behaves more like a stretched version of a geosynchronous equatorial orbit.
The satellite would spend most time near apogee over one equatorial longitude band, then quickly pass perigee on the opposite side — but both apogee and perigee dwell zones would be over equatorial/low-latitude regions, not high latitudes.
There is no “Molniya-like” advantage for polar/high-latitude coverage — equatorial regions already have excellent coverage from ordinary geostationary satellites.
The frozen-orbit property is lost, so long-term station-keeping would require more fuel to counteract perigee drift.
Related Equatorial-Friendly Orbits
Geostationary orbit (GEO) — circular, 0° inclination, 24-hour period → constant position over equator.
Geosynchronous equatorial orbit — can be slightly elliptical, still 0° inclination.
Highly elliptical equatorial orbits exist in theory (and have been studied for some niche uses), but they are not called Molniya orbits and do not serve the same purpose.
In short: You can put a highly elliptical ~12-hour orbit in the equatorial plane, but it would not be a Molniya orbit, would not provide the characteristic high-latitude dwell, and would lose the key frozen-orbit stability that makes real Molniya orbits practical and long-lived without excessive station-keeping propellant. The “Molniya” name and concept are tightly bound to the ~63.4° inclination for northern high-latitude service.
Those clever Russians!
Where would Sirius XM satellite radio be without the Russians?
I’m sure they’d (Russians) be so proud of providing the technology to take Howard Stern and Def Lepard global…
They also pioneered the Tundra and Super Tundra orbits. These have the same inclination as the Molniya orbits, but 24 hour instead of 12 hour period. They aren’t as eccentric as Molniya orbits, ranging from e = 0.2 to e = 0.3, rather than 0.7 to 0.74. Their perigee is thus much higher, An orbit with e = 0.25 would have a perigee of 25,000 km, and an apogee of 46,000 km. The period is determined by the semimajor axis – as long as that is 42,000 km, the period will be 24 hours. A Molniya orbit is easier to reach, but a Molniya orbit will traverse the Van Allen belts four times a day, while a Tundra satellite only goes through once, on its way to its final orbit. The whole point of either is to give the Russian ground stations, many of which are at high latitude, a higher elevation look angle than they can get with a geostationary satellite.
A very, very small consolation to those who lost their lives to NASA: I developed a training session for our youngling engineers based solely on NASA incidents – change management, consistency in engineering units (yes, this had to be taught), following procedures, and being smart enough and brave enough to stop when things don’t look right. And, most importantly, never, ever confusing being lucky with engineering discipline.
So, I have finally gotten around to watching (some of) “For All Mankind.” If I have it right, the way to avoid the Challenger disaster was to put women in charge of everything.
Women are so cool!
“For All Mankind” is an alternate view of reality one comes to when the pressure in one’s space suit gets lowered enough…
We watched all the seasons. Basically soap opera but the scenes on and approaching the Moon in the first season were awe inspiring.
The Molly Cobb character was a good value person.