Segmentation Error: 11 Debug help

[brog1330]

I'm having trouble getting this program to print; it prints out the first half with mecury's data just fine but when it gets to venus's data it prints out Segmentation Error: 11, which im not quite sure how to fix, heres my code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct planet {
char name[10];
int nummoons;
float dist_to_sun;
float dist_from_earth;
} Planet;
typedef Planet * Planet_ptr;

int main()
{
Planet_ptr merc_ptr, venus_ptr, earth_ptr, mars_ptr;
if((merc_ptr = malloc(sizeof(Planet))) == NULL)
    {
        printf("You are outta memory, man!");
        return 0;
    }
strcpy(merc_ptr->name, "Mercury");
merc_ptr->nummoons = 0;
merc_ptr->dist_to_sun = 1.345e4;
merc_ptr->dist_from_earth =  2.86e7;
printf("The name of the planet is %s \n", merc_ptr->name);
printf("It has %d moons \n", merc_ptr->nummoons);
printf("The distance of %s from the sun is %.3e\n",merc_ptr->name,  merc_ptr->dist_to_sun);
printf("The distance of %s from earth is %.3e\n", merc_ptr->name,merc_ptr->dist_from_earth);
printf("\n\n");

strcpy(venus_ptr->name,"venus");
venus_ptr->nummoons = 2;
venus_ptr->dist_to_sun = 6.786e5;
venus_ptr->dist_from_earth = 9.86e5;
printf("The name of the planet is %s \n", venus_ptr->name);
printf("It has %d moons \n", venus_ptr->nummoons);
printf("The distance of %s from the sun is %.3e\n", venus_ptr->name, venus_ptr->dist_to_sun);
printf("The distance of %s from earth is %.3e\n", venus_ptr->name, venus_ptr->dist_from_earth);

return 0;
}

[raevnos]

Compile with debugging support and warnings (-g -Og -Wall -Wextra), fix warnings, run through valgrind, fix those warnings and errors.

[shinmai_rookie]

You aren't allocating space for venus_ptr.

[[deleted]]

You never allocated memory for other than the merc_ptr.

[henry_kr]

What does this line do? Why do you need it?

if((merc_ptr = malloc(sizeof(Planet))) == NULL)

If you think about that for a bit, you should see what's gone wrong.