Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [jpl-horizons]

Questions relating to the JPL Horizons solar system data and ephemeris computation service

2
votes
0answers
46 views

What happened to time in 1962? (JPL Horizons changes displayed time from UT1 to UTC for dates starting in 1962)

I was viewing some observer output from JPL Horizons while writing this answer and I saw this annotation. "Prior to 1962, times are UT1. Dates thereafter are UTC". Presumably users of JPL's Horizons ...
0
votes
0answers
21 views

How exactly to use astroquery.jplhorizons to get the state vectors of Mercury and the Parker Solar Probe?

In the question Is the Parker Solar Probe's semimajor axis being so close to that of Mercury's just coincidence? Does it help somehow? I used a Python script to plot the heliocentric orbit of the ...
4
votes
1answer
129 views

How is the Chebyshev method used by JPL?

In the DE packages, NASA gives us a series of coefficients for the Chebyshev approximation. As I understand it, those approximations are given by a series of polynomials $T_n$ for the interval $[-1,1]$...
4
votes
2answers
68 views

How to show spacecraft position, heading etc relative to an asteroid

Given all the cool asteroid and comet missions out there (OSIRIS-REx, Hayabusa2, etc) I want to track the approach of the spacecraft to the asteroid. My favorite tool, JPL Horizons, can provide highly ...
1
vote
1answer
40 views

Calculation of Sun-Satellite and Moon-Satellite distance

I have the coordinates of a satellite in the Earth Centered Inertial frame. I have calculated the Sun-Earth and Moon-Earth vectors using the JPLEphemeris package. Now I have to calculate the Sun-...
3
votes
0answers
89 views

Sources for SPICE Kernel (SPK) files for asteroids

Besides the official source for SPK files (ftp://ssd.jpl.nasa.gov/pub/eph ...) is there a place where people upload kernels for the smaller bodies in the solar system? I was looking for the Jupiter ...
1
vote
1answer
84 views

Difficulty trying to use the SPK file ast343de430.bsp

I'm looking for a NAIF SPK file (these typically end in .bsp) for a bunch of asteroids in the J2000 reference frame. I found ...
4
votes
1answer
160 views

I've almost learned to spell Chebyshev, why has JPL switched to Hermite interpolation for DE438?

According to @ChrisR's thorough answer One caveat however is that the interpolation in DE438 is a Hermite interpolation, and no longer a Chebychev interpolation, so you may need to update your code....
4
votes
1answer
77 views

What are the problems that need to be taken in consideration when trying to find planetary position by using jpl ephemerides?

I'm currently trying to determine the position of the sun and the moon from jpl ephemeris DE200 which is referred to the dynamical equator and equinox of 2000 and uses tdb time. I am using the j2000 ...
2
votes
0answers
57 views

Will these equations give me the approximate apparent RA and Dec using positions from Horizons?

In this answer @DavidHammen showed me how to get coordinates from JPL's Horizons using the Earth's equatorial plane as a reference plane by selecting ...
1
vote
0answers
45 views

How does JPL calculate Epochs for generating ephemerides?

How exactly do epochs fit into the computational propogation of data of NASA's Jet Propulsion Laboratory and what methods do they use to calculate the properties of those epochs in the first place? ...
2
votes
1answer
55 views

Plotting error values between simulated and JPL data

I'm attempting to compare values between my simulated data for the solar system and the official JPL data, to find errors for the position, velocity, inclination and azimuth. The simulated data was ...
1
vote
0answers
108 views

How to get the coordinates from NASA JPL Ephemerides DE430 ( ECRS) to ECI?

I'm trying to make a software that determines the orbit of a satellite which is affected by the Sun and Moon. The coordinates [x y z] that I have for the satellite are in Eci. For the position of the ...
4
votes
1answer
221 views

What is the difference between GCRS and J2000 frames?

What is the difference between GCRS and J2000 frames? Which is commonly used worldwide in satellite communications? I've read a statement here, that ...
2
votes
1answer
169 views

Why does this site show Starman's position so far from what Horizons gives?

As this answer mentions, there have been several questions about the data represented on the whereisroadster site within the Space Exploration Stack Exchange site. One about wrong distances has been ...
2
votes
2answers
368 views

What does “coord@10” mean exactly as a target for JPL's Horizons? How to access it?

According to this answer, using "coord@10" as a target code for JPL's Horizons represents the motion of a hypothetical location on the Sun's surface; presumably as a way to represent the rotation of ...
32
votes
2answers
5k views

Why does this plot show Starman's speed relative to the Sun fluctuating so often?

After the launch of Starman, during the inaugural flight of SpaceX's heavy lift vehicle, the Falcon Heavy, PearsonArtPhoto set up a website to track various stats about Starman and his Roadster. A ...
2
votes
2answers
141 views

Calculating spacecraft thrust manoeuvres with JPL data

I've recently programmed an animated simulation of the main elements (core planets and Sun) of our solar system: by using the initial coordinates from the JPL (Jet Propulsion Laboratory - NASA) ...
5
votes
2answers
204 views

JPL Horizons ephemerides

I'm simulating the Sun-Earth-Moon system by numerical integration of equation of motion. I've confused a little bit in JPL Horizons ephemerides. Could anyone explain (if possible, on pictures), how ...
10
votes
2answers
834 views

Why is the sidereal period of the Earth 362.392667 days?

Using JPL's Horizons API I can look at the orbital elements for the EM Barycenter wrt the Solar System Barycenter at J2000. The output looks like this: Watch for the PR (Sidereal orbit period) ...
4
votes
0answers
142 views

Ecliptic reference frame for satellite orbits in JPL Horizons

I'm trying to get orbital elements for natural satellites of all the plates with respect to their system's barycenters and I don't see how it is possible that using the ecliptic as a reference plane ...
4
votes
1answer
252 views

Compatibility of osculating elements and cartesian vectors given by JPL Horizons?

I'm facing a problem I can't explain and I would like to know if someone has more information about it. I'm drawing a solar system and when I plot earth with the Horizon cartesian coordinates, it ...
2
votes
2answers
416 views

How to calculate the planets and moons beyond Newtons's gravitational force?

The question Calculating the planets and moons based on Newtons's gravitational force was pretty much answered with two items: Use a reasonable ODE solver; at least RK4 (the classic Runge-Kutta ...
9
votes
1answer
445 views

Where to find the best values for standard gravitational parameters of solar system bodies?

Where can I find the best values to use for standard gravitational parameters of solar system bodies for numerical simulation experiments? Here are two sets I've put together. The first set is from ...
1
vote
1answer
120 views

Discrepancy between HORIZONS and SPICE

I am trying to reproduce the output of the HORIZONS system using the SPICE toolkit from NASA, but I am not getting exactly the same results. I am using this script to compute the position and velocity ...
1
vote
0answers
65 views

ISEE-3's L1 halo orbit's Spice kernels still available or requestable? (1978-82)

When I was looking for previous calculations for JUNO I received help which pointed me here. Now I'd like to review ISEE-3's orbit and compare it to calculations since receiving this welcomed answer. ...
3
votes
2answers
510 views

How do we track the exact location of the spacecraft which is millions or billions of miles away from us?

How do we track the exact location of the spacecraft which is millions or billions of miles away from us? What things do we study for tracking purpose? How exactly do we predict?
0
votes
1answer
109 views

How can the data rate be increased in the space which is full of noise?

I am curious to know what can we do to improve the data rate in the space? I see that there are some noise sources in the Space that affect the signal quality between ground stations & deep space. ...
9
votes
2answers
321 views

Why do the LRO's orbital elements appear to constantly oscillate - except recently?

I plotted some of the orbital elements of the Lunar Reconnaissance Orbiter from JPL's Horizons database, and I see that there are constant oscillations. The period of the semi-major axis and ...
1
vote
1answer
179 views

Ephemeris for lunar body-centered body-fixed coordinates?

I'm going to try to do a modest simulation of the Moon's nutation as seen from the Earth (geocenter), similar to the technical one's I've shown in this question. I'll do it in Python and render it in ...
7
votes
1answer
291 views

Unravelling Cassini's “ball of yarn” orbit around Saturn, tabulation of propulsive maneuvers?

The cool GIF on the NASA JPL Cassini resources page All Orbits (2004-2017): The Ball of Yarn is quite beautiful to look at, but it also hints at some beautiful engineering and orbital mechanics as ...
6
votes
1answer
364 views

Is Cassini's 183rd burn; some kind of engine record?

I've just read that when Cassini makes its first close pass of Saturn's F-ring on December 4, it will be the 183rd engine burn which sounds like a lot for orbital maneuvers using a spacecraft's main ...
4
votes
2answers
262 views

Juno's original orbit around Jupiter - is this apsidal precession? If so, need expression

Below is a plot of Juno's originally planned orbit around Jupiter, extracted from JPL Horizons. It's shown in J2000 ecliptic coordinates, centered on the Jupiter barycenter. It turns out the orbit is ...
4
votes
1answer
205 views

JPL Horizons original reference orbit data for Juno - how to retrieve now that it's been updated?

Because of the slow helium valve responses, Juno was not instructed to execute the large delta-v maneuver to drop from the ~53 day orbit to the ~14 day orbit originally scheduled for 2016-Oct-19. I'd ...
1
vote
1answer
199 views

How to find more information about Chang'e-2's actual 3D orbit in space, since it's not in JPL Horizons?

edit: A simple web search in Chinese may turn up something, but I don't know anyone personally who is both both fluent and interested in space exploration. This is a pretty cool orbit - there must be ...
1
vote
1answer
121 views

How to know when JPL Horizons is updated with new Juno spacecraft trajectory?

I "watched" Juno's flyby of Jupiter using the simulation in the NASA's Eyes app on my laptop, and later saw the good news in this tweet. Now I want to do a "flyby in Python". Using the setup (shown ...
9
votes
1answer
789 views

Is this what station keeping maneuvers look like, or just glitches in data? (SOHO via Horizons)

I've been enjoying the JPL Horizons web interface and after I discovered the incredibly extensive database associated with SOHO (Solar and Heliospheric Observatory, also see sohowww.nascom.nasa.gov) ...
4
votes
2answers
835 views

Python API for JPL Horizons?

I found the python package HorizonJPL in the Python Package Index, but it looks like it's limited to activity in 2013. When I go to the linked documentation page https://docs.google.com/document/d/...
16
votes
2answers
1k views

How can I derive an asteroid mass/size estimate from JPL parameters?

I want a list of objects with a semi-major axis between 0.95 AU and 1.05 AU that are probably larger than 1 km in diameter. For this, the JPL Small-Body Database Search Engine seems to be the best ...